Nano Biomedicine - Science topic

Ali Safaa

1.Pyocyanin can be adsorbed on the surface of gold nanoparticles. It does not oxidize or reduce gold. Gold is oxidized with potassium cyanide or aqua regia.

2. When interacting with gold ions, Pyocyanin (quinone) acts as an oxidizing agent.

3. Pyocyanin melting point 133 0С.

you welcome

Hi Milena,

Based on my experience I used the centrifuge to precipitate the polymer and after that, I used the freeze dryer to remove the water.

Dear Ehsan Razeghian, the choice of the solvent has a detrimental role for success. Methanol is usually the best option. Please have a look at the following documents. My Regards

Riaz A. Khan recovering the ethanol and reuse it for the next batch of mesoporous silica nanoparticles.

Kira, Unfortunately, this question is not in the area of my expertise. I would be conjecturing too much to qualify the answer as scientifically validated. I apologize.

I wish that there was an easy answer. TEM is probably the best absolute measurement approach, but it requires being careful about statistics, and being aware of artifacts associated with drying the sample. DLS is in principle better for hydrated systems but at high ionic strength aggregation is likely. The tradeoffs are presented well here:

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Dear Saravanan Arumugam thanks for sharing this very interesting technical question with the RG community. Personally I'm not an exert in this field of reserach (we are inorganic / organometallic chemists) and I was not even aware of the fact that hetero-atom-doped carbon dots have antibacterial properties. However, there are various reports in the literature in which this effect has been demonstrated. For example, please have a look at the following potentially useful articles which migth help you in your analysis:

and

The first article is freely available as public full text, while the second has been published Open Access (please see attached pdf file). Apparently it might be worth a try using the hetero-atom-doped carbon dots in combination with copper or silver nanoparticles for enhanced antibacterial activity.

Good luck with your work!

Santosh K. Tiwari Thank you for responding I'll look into these

Current trend is Nanotechnology based drug delivery systems like nanogels, Hydrogels for wound healing, surgical sprays, Monoclonal antibodies are in high demand in this covid state and many companies are even having patents.

Dear Hevar, several multiple factors are responsible for antimicrobial resistance. These include suboptimal prescribing and inadequate adherence to completion of prescribed antibiotic courses, misuse and Over use of antibiotics in humans and animals and Poor infection prevention and control in health care settings.

Muhammad Sadeq Ale.Isaac

Discussion of the problem in this place raises questions that need to be constantly asked to each other. If you want me to help you, write in detail the composition of your mixture and your actions, your problems in a personal letter.

Dear Naime,

I suggest that you read the following paper:

Please let me know if you are unable to download it.

Kind regards,

Bahram

Hello,

The release profile of the encapsulated drug in strongly influenced by the characteristics of the release medium. For instance, low solubility of the target chemotherapeutic in the employed release medium might be the reason for your observations. Several other factors such as stability of the carrier and interactions between drug and carrier could also affect the release profile. Overall, all of these factors must be carefully considered in order to draw an accurate interpretation.

Furthermore, drug encapsulation efficiency and release profile are two independent factors and in some instances, one might not even be affected by the other, therefore, it is best not to use one of these factors for interpretation of the other one.

Amr Mahmoud Scale-up of nanoparticles needs optimization as most nanoparticle synthesis is easy at small amounts. In this case, I would suggest using a higher concentration or molecular weight of PEG. The following article might be of some help to you. " Challenges posed by the scale-up of nanomedicines " DOI: 10.2217/nnm.12.3

Dear all, solubility depends on the chemical structure and types of existing intermolecular forces. Excessive sonication may degrade any of the compounds present in the recipe. There are many techniques to solubilize poorly soluble drugs. Please check the following links. My Regards

Silver nano-particles are toxic to varieties of organisms. Silver-based biocidal material is used for commercial & healthcare textiles.They have exhibited 99% efficacy against the spread of bacteria. They also showed a broad spectrum.fungicidal activity. As far as the mechanism of action is considered Silver nano-particles release silver ions, which act as the biocidal species .

Naeimeh Hassanzadeh Goji Anytime. I did not also find the hydrate structure. Maybe it hasn't been reported, yet. You can give it a trial. Good Luck!

I don't think, it would be much toxic then. If you are working in applications where biocompatibility really matters, then you may do some standard toxicity tests for better acceptability of your publication. But, if you are working in physical or engineering aspects, you may simply ignore it...

I invite you to read my paper

Kind regards

It could be useful

https://www.researchgate.net/publication/276835325_Alginate-pomegranate_peels'_polyphenols_beads_Effects_of_formulation_parameters_on_loading_efficiency

Dear Soudabeh,

I had immobilized my enzyme and observed a change in the Km value. However, mine was a single substrate specific enzyme. I second the opinion of Tapan Kumar; the pore sizes, the immobilization technique used, etc., could play a role in the availability of the reactive site to your substrate.

One of the most important applications is the treatment of cancer

https://www.nature.com › gene therapy › news and commentary

It is so challenging to get stable nanoparticles with high drug loading. Moreover, active targeting has many limitations that impede its applicability.

Reminds me of: 'In theory, theory and practice agree. In practice they do not'

I would always believe one well-conducted experiment over one paper with more Greek letters than an Athens post-office.....

Gold and Silver nanoparticles is seen in Alternanthera sessilis

Subha Kandiyar we are washing in order to remove the un-reacted moieties and the loosely bound capping agent. So that the surface of our nano are free for activities

1) You must allocate at least 3 hours per day to research

2) Read the latest research in your specialty

3) Communicate with researchers from other countries

4) Try to find new search points

Best Regards Mohammed Hamada Musleh

Hello, Nusrat Afzul,

Have you solved your mol% problem, please?

If not, I might help you here. I am looking forward to hearing from you.

Please see some links about ZnS nanotubes in the attached file.

DNA base blending is easy to display (in any event on an abnormal state) and therefore simple to program, while supplanting the 3'- OH assemble with SH influences them to cling to gold nanoparticles.

In the papers depicted in the connection, there are three sorts of items included: gold nanoparticles, non-complimentary 3'- thiol DNA oligonucleotides, and a connecting DNA duplex.

Foundation for those new to sub-atomic science: DNA is a polymer whose rehashing unit contains a phosphate gathering (PO4), a ribose ring, and a DNA base, which can be either Adenine (A), Thymine (T), Guanine (G), or Cytosine (C); the phosphate gathering and ribose ring don't change. The Carbon molecules in the base are numbered 1 through anyway numerous that base has, and those in the ribose are numbered 1' through 5'. The 5' carbon of the ribose ring is covalently attached to one of the oxygens of the phosphate gathering, while the 3' carbon of the ribose ring is clung to (an alternate) one of the oxygens of the following phosphate gathering; thus researcher usually allude to the "5' end" and "3' end" of a DNA strand. The phosphate at the 5' end of a strand "typically" just won't have anything bound to it (albeit now and then the 5' end of a DNA or RNA strand will get changed with the end goal of some phone procedure); while 3' carbon of the base at the 3' end of a strand will have an OH bunch rather than the O of the following phosphate. The 1' carbon is clung to the base. The structure of the bases implies Adenine and Thymine bases of various strands normally frame hydrogen bonds with each other (A with T, not A with An or T with T), as do Guanine and Cytosine, so if two DNA strands which have long strings of corresponding arrangement (frequently regardless of whether a couple of bases are befuddled), they will normally shape into the celebrated twofold helix shape. The supplement of a strand's succession is acquired by turning around the grouping and after that trading A with T and C with G, since this base blending is constantly antiparallel. This makes DNA effectively "programmable", since in the event that you need two things to tie, make two integral DNA successions, connect balanced and the other to the next.

This programmability of DNA strand restricting is the fundamental purpose of the paper. Initially, single strands of DNA are appended to gold nanoparticles by supplanting the OH assemble on the 3' carbon of the 3' end ribose with a SH (sulfur + hydrogen, otherwise called thiol) gathering, which ties to gold. (Sulfur has numerous comparable synthetic properties to Oxygen, being in a similar section of the intermittent table, so the substitution is sensible.) In a basic model, you would append say TTAG (DNA groupings are by and large composed from the 5' base; for this situation the ribose of the G base would have the thiol gathering) to one nanoparticle and CTAA (the integral arrangement) to alternate; this won't work for one, and perhaps two reasons. The first is that the more bases in a corresponding succession, the more grounded the bond is, and 4 bases happens to be not sufficiently solid to hold together at room temperature. (From the heuristics I utilize, despite the fact that I don't really utilize these a considerable measure so they may be off, 5-7 bases at room temperature is generally equivalent vitality bound versus unbound and in this manner will return and forward, while essentially more will remain bound and fundamentally less won't tie for any apparent time allotment. For this reason, the creators need something to remain bound at room temperature, and afterward unbind at higher temperature. The 8-base succession they utilize, so they assert, has a dissolving temperature of 42 degrees C.) The second, which they don't discuss, however I think, might be that the separation of a short arrangement is too little and would be liable to steric obstruction; the nanoparticles being not able get that nearby. On the off chance that that is not valid, at that point it's not by any stretch of the imagination clear to me why they utilize the linker duplex.

Along these lines, the writers join AGTCGTTT-3'- thiol TACCGTTG-3'- thiol strands to the gold nanoparticles, which are not reciprocal to each other (or to themselves; self-complementarity is every so often an issue in strand plan) and in this manner don't associate, yet. They at that point include a linker duplex, made out of ATGGCAAC-TATACGCGCTAG and CTAGCGCGTATA-AAACGACT strands. Note that the 12-base spaces of the linker strands are integral to each other, while the 8-base areas are every corresponding to one of the thiol oligonucleotides. Along these lines each thiol-oligonucleotide hybridizes to one of the strands in the linker duplex, which hybridize to each other, shaping an association between two nanoparticles. Since each nanoparticle has various strands of whichever compose it has, and there are a ton of duplicates of linker duplex in arrangement, totals shape

regards

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Here is the NAMD mailing list where Josh answered me exactly how to do that along with all details :

you can use HPLC with program sequence of diffrent lamda maxima & can anlyze the release quantity of drug.In primary stage you have to validate your method.

Hello

This is an interesting topic.

Zn is useful in the body in very small amounts and ZnO helps to enrich the blood with oxygen. This makes it possible to enrich the regeneration of red blood cells. The remaining Zn is excreted through the syringe system or accumulates in the bones if it is in increased doses.

Hope This paper can help:

Our group has been working for developing nanogap by atomic layer lithography in which the gap width is determined by the atomic layer deposition (ALD). Alternatively, CVD or molecular beam epitaxial are also applicable for defining the gap-width. The gap-width can be down to a few nanometer to sub nanometer. Here is a list of some of the publications where you can find the fabrication techniques. 

Dear Chaedong,

I don't get the complete picture from just the text description. In the beginning you mention no ligands, you just state that the particle is amine rich; is there also a flexible chain involved (steric interactions) or just the charge? Maybe a drawing of your ligand structures and what you think is happening would make it easier to comment on.  

dear Amr

GC-MS  is suitable for your study

good luck

alfekaiki

Thank you Swati.

I will suggest you to use succinic anhydride to add COOH group to terminal OH..

In my opinion it is not necessarily the problem of your system but rather of the duration of your centrifugation step. Derived from the Stokes equation you obtain the following expression for the settling velocity of your particles:

V = d^2 (p_p - p_f)*g/(18*n)

where V is the settling velocity, d is the particle diameter, p_p is the particle density (for chitosan-TPP particles ~1.3 g/cm^3), p_f is the fluid density (~1 g/cm^3 for aqueous solutions), g is the gravitational force during centrifugation and n is the viscosity of the fluid (~1 mPa*s for aqueous solutions).

You can repeat the math, but to isolate particles in a small reaction tube (1 cm) with 250 nm you need to centrifuge ~16 min at 10000g. However, if you also want smaller particles from your distribution, say all particles up to 150 nm, you need to centrifuge for ~45 min. I also attach an excel sheet with the calculations.

If you now measure your isolated particles, they will always be bigger than the original population since you loose small particles during the process. If after this, your particles are still too big, then there is probably a problem with the stability of your system.

if u want to synthesize silver NPs go for currry leaf extract since it contain carbazoles or go for neem leaf extract. it will produce NPs within some hours.

You shouldn't use a too good solvent for the drug; then the drug will rather remain in the solvent phase than adsorb to the silica surface. Actually wrote a paper on this almost ten years ago ;-) http://www.sciencedirect.com/science/article/pii/S0168365908001211

With loading time increasing, the loaded amount will tend to saturation state. So yes, if you increase loading time, the loaded amount may increase but usually not much. Also, 24 hrs is not a fixed time for drug loading. The properties like hydrophilic or stability will also influence it. The factors influencing drug loading mainly focuse on the loading method (linkage, encapsulation et. al), properties of drugs (hydrophilic or hydrophobic, stability et al.), properties of nanomaterials (porous structure? 2D material? surface functionalization?), and the environment (temperature, pressure, properties of solution system et. al). Many works has paid attention on this domain. You can find some related review and read it.

Dear Aswathy J.:

See our article on the effect of small concentrations of the nanoparticles on plant development. They will be useful for your work.

Best regards.

SPR is the excitation of surface electrons. Increase in size will lead the red shift means decrease in the surface electrons

Agree with Aki. Dear Nejad change in colour is due to the change in size of your nanoparticles

It will depend on how your proteins binds - interacts with the material - you have to optimise the time for digestion - you may have a look at the following publications. You may also have to look into additional proteases other than trypsin.

For Gadolinium, see nephrogenic systemic fibrosis in patients with kidney disease.

Load your drug on a suitable polymer (biodegradable ones are the best) then use electrospinning at high voltage after dissolving the polymer loaded drug in a suitable solvent (water is not preferred) to make a scaffold of the polymer bearing the drug. Many articles are available in this field. You can use the keywords you have like the name of the drug, the polymer, the solvent together with the word electrospinning to get a unique result.

Hi Chris,

i don't see why not. It well know that liposomes can be loaded into hydrogel. the question is:  will the get out? but to know that you'll have to try.

one important thing is to make sure that the PGLA solution and the liposomes suspension have the same osmomolarity otherwise you will destroy them.

check the literature for liposomes in hydrogel you'll find some already working system.

hope it helped

regards,

Etienne

Dear Doaa Abdelmonsif ,

 Please find the below patent for  Process for the Egcg stabilized gold nanoparticles and method for making same 

Patent no :WO 2014071190 A1 I hope my answer is helpful for you.

Hi Yong, did you separate the Au NPs from unreacted 3MPA before the EDC/NHS reaction?

Also, since DOX has one primary amine, it is probably worthwhile to do a one pot reaction of Au-NP-COOH + DOX + EDC in MES pH 5.5 and forget about making an NHS intermediary.

What type of vesicle you are working on?

Hi Eduard,

I have had some experience in the past conjugating proteins bearing a thiol to maleimide functionalised nanoparticles (that case gold: https://www.researchgate.net/publication/265733952_Monovalent_maleimide_functionalization_of_gold_nanoparticles_via_copper-free_click_chemistry/stats).

You reaction is slightly different, in that your Ab will have quite a few thiols (how many you have you could estimate if you know the mAb structure).  My concern would be that if there are a lot of thiols on your antibodies is that you could possibly cross-link particles if the concentration of thiol-mAb is low, which I guess would be bad for you.  My advice would be to have the antibodies in a huge excess (conc. you will have to determine for yourself) over the nanoparticles, to minimize this problem.

Then you can purify your particles from the remaining unreacted Ab's.

Good luck!

I do not think that starch can be truely *dissolved* in water, it just forms a *dispersion*; the colour change will be due to the dispersed particles' particle size.

It is important to use correct terms, why using "dissolve" if it in contrast forms a *dispersion*? thermodynamically spoken, there can be no bigger difference between a solution and a dispersion, because a solution is an equilibrium system, a dispersion is a non-equilibrium system, i.e. *minimum* vs *maximum* energy content, or in other words: by dissolving, the system will walk to a lower energy level, by dispersing, you introduce energy from outside and finally reach a (much!) higher energy level than before.

Entrapment efficiency gives you an idea about the %drug that is successfully entrapped/adsorbed into nanoparticles. It is calculated as follows:

%EE = [(Drug added - Free "unentrapped drug")/Drug added] *100

Example: If the %EE is 30%, it means that 30% of your drug is entrapped into the nanoparticles.

Loading capacity helps you to deal with nanoparticles after their separation from the medium and to know their drug content. It is calculated using the following equation:

%LC = [Entrapped Drug/nanoparticles weight] * 100

Example: If the loading capacity is 30%, it means that 30% of the nanoparticles weight is composed of the drug! i.e. Each 1 mg nanoparticles contains 0.3 mg drug.

Dear Ahmed,

In Zero Order Kinetics, the rate of a reaction does not depend on the substrate concentration. In other words, saturating the amount of substrate does not speed up the rate of the reaction. Linear line is obtained when plotting a graph of time (t) vs. concentration [A] in a zero order reaction; the slope of this plot is a straight line with negative slope equal negative k, the half-life of zero order reaction decrease as the concentration decrease.

The zero order kinetic rate law is as followed, where [A] is the current concentration, [A]_0­ is the initial concentration, and k is the reaction constant and t is time:

[A]=[A]₀­−kt    

In order to find the half life we need to isolate it on its own, and divide it by 2. We would end up with a formula as such depict how long it takes for the initial concentration to dwindle by half:

t_1/2=[A]₀­/2k

The t_1/2 formula for a zero order reaction suggests the half-life depends on the amount of initial concentration and rate constant. 

Therefore, in order to find the value of time required for release of 50% of drug content, you should divide the initial concentration by twice the reaction rate that you get from the slope of the linear plot.

Hoping this will be helpful,

Rafik

Hey,

Please have a look here

You have to use a good experimental design software for your work!

You can see my new publication in below link

Hello,

Iron nanoparticles are dense and solid spheres and they will not be soluble in any solvent. Citric acid capped very small particles of iron are only soluble in water and some solvents. The polymer coating will completely modify the properties of the underlying nanoparticles. You have not specified the polymer incase it is a biocompatible and water soluble polymer then only the particles can be soluble but it strongly depend upon the core diameter. Anyway you will get huge no. of references reporting iron oxide OR iorn nanoparticles for biomedical use and their interaction with cells. It is a well explored topic of research.

Hello,

You should specify which type of silver you want to measure.

If you wish to measure total silver (soluble + insoluble) you can performe nitric acid digestion and atomic absorption spectrometry.

If you want to measure soluble silver, you should first ultracentrifuge the solution to sediment the insoluble silver particles. Then use supernatant to measure silver as mentioned above.

Subtract soluble silver from total silver to attain insoluble silver.

If you want to determine silver as ppm scale, you can use all atomic absorption spoctrometry methods.

Polydispersity Index is dimensionless and scaled such that values smaller than 0.05 are rarely seen other than with highly monodisperse standards. Values greater than 0.7 indicate that the sample has a very broad size distribution and is probably not suitable for the DLS technique. The various size distribution algorithms work with data that falls between these tow extremes. The calculations for these parameters are defined in the ISO standard document 13321:1996 E and ISO 22412:2008

The preparation should be possible with nearly any modification (anion). But use the special properties of the material (that means magnetic sedimentation) in combination with dialysis. You may find a simple procedure within the attached publications.

Microspheres should remain in the myocardium for prolonged periods. In years past we did such experiments and waited weeks between measurements. Are you obtaining a reference blood sample during microsphere injection? This is essential if you want to accurately quantify regional blood flow. Also, I would use adenosine rather than dobutamine.

You can please download pdfs of the files attached herewith.

You may need to reduce the quantity of PEI.  Alternative way is to adjust the pH of PEI-Dexamethasone solution to around pH 4 using acid prior to  lyophilization.  Note PEI is insoluble in cold water.

Dear Shailendra Singh,

The best option would be to use the Magnetofection*** method for in vivo transfection.

Magnetofectin uses magnetic nanoparticles to complex nucleic acid to deliver and thus, when injected in vivo, the transfection can be targeted simply by an external magnetic field developped by a small magnet.

you can find more information on the in vivo method and on our reagents dedicated to this application, in the following links.

Would you have any question, please do not hesitate to contact me directly at tech@ozbiosciences.com or via ResearchGate.

Good luck with your experiment,

best regards,

Cedric

MAGNETOFECTION

*** The Magnetofection technology uses a magnetic field to attract and concentrate complexes of magnetic nanoparticles and nucleic acid onto the cell surface as demonstrated by Grześkowiak BF et al, Pharm Res. 2014 Jul 18. (http://www.ncbi.nlm.nih.gov/pubmed/25033763).

You will face problems, serious problems, going for oral delivery of nanoparticles. It is not impossible, but they really have to deal with lots of unfavorable conditions in the GI tract, mainly acidic gastric environment and the continuous secretion of mucus that protects the GI tract.

So, you have to find something which is acid resistant (and this likely takes all the polyesters out of the game, even though PLGA/PLA, with and without PEG have been used) and can adhere and permeate the mucus. This limits the choice to polysaccharides (better if they contain a glucosamine unit), methacrylates and polysterene particles, which of course are not biodegradable.

Ideally, you may want to try to cover PLGA particles with chitosan, but you will have major problems encapsulating the enzyme in this system.

Ionic bond is highly sensitive to pH so if you claim that your nanoparticle-bacteria complex interacted through ionic bond you should somehow show that at an special range of pH, nanoparticle-bacteria complex is formed and at other pH values this bonds break. So a simple pH titration via simple spectroscopies which depend on nanoparticles type  should be done. For example in the case of gold, silver or Zno(zinc oxide) nanoparticles you can use Uv-Vis spectroscopy.

Best wishes 

If you want to do it theoretically, then I think it may be even harder. Unless you simply model ideal conditions, like having 86000 lipid molecules per 100 nm diameter, single bilayer, perfect spherical particles and 100% incorporation of DSPE-PEG (you should know the molar ratio at which you add it).

I would be already quite careful with taking 86000 lipids/100 nm in case of PC, since you have a mixture of saturated and non-saturated side chains, sometimes of variable length too, that would not pack as well as phospholipids with defined saturation and length.

Even then, you have to know if the 86000 lipids are calculated based on their volume or on their surface. From that, you could simply calculate the ratio between a sphere of radius 50 nm and a sphere of radius 40 nm (surface of a sphere: 4 r^2 pi, volume 4/3 r^3 pi).

Once you found out the number you want, just multiple by % DSPE-PEG and you will get the number of DSPE-PEG molecule in the vesicle. But again, this is a very coarse approximation, which doesn't take into account packing of lipids and cholesterol.

Another method, if you are familiar with modelling (and I am not), would simply be to feed a simulation with the expected number of molecule of PC, DSPE-PEG and Chol and see if you end up having liposomes of approximately 80 nm. Maybe you can also constrain the size to 80 nm and the see how many molecules are forming the actual vesicle.

Agree with Tian.  I obtained similar data for some plant extracts and higher readings were actually due to extract interference. If you want to do various time points, try using a negative control (medium + nanoparticle + WST1 without cells) for each nanoparticle concentration.  Subtract these readings from experimental with cells.

Hi Ronak,

You may quantify the trace of carbon (cdots) coated on particles by the followings:

1) TEM and EDAX

2) Fluorescence spectroscopy (e.g. quenching effect of nano particles)

3) UV/vis spectroscopy

It depends a lot on the setup of your experiment. Is it an in vivo or an in vitro protocol?

For an in vitro experiment, adding a poloxamer in the formulation may not be very useful, unless you want to prepare for an in vivo assay.

thank u so much nicholas :) 

my drug has only one -COOH group. The book you mentioned, I will surely refer to that.  

Dear Annette,

Wavelengths below 210 and above 400 nm can be eliminated with a filter solution (1.14 mol l⁻¹ NiSO₄ / 0.21 mol l−1 CoSO₄ / 0.01 mol l⁻¹ H₂SO₄).

G Michael

Refer 

Synthesis and Self-Assembly of Cetyltrimethylammonium Bromide-Capped Gold Nanoparticles, Langmuir 2003, 19, 9434-9439

Better way you can use the permeable membrane, which resembles the skin. Then by using physiological buffer you can measure how much amount of nano-particles crossed that membrane.

Thanks both you for your answer.