Jaime Ruiz-GarciaUniversidad Autónoma de San Luis Potosí (México)
Jaime Ruiz-Garcia
BSc: ITR-Zacatepec (México); PhD: University of Maryland at College Park (USA); Postdoct: University of California Los Angeles (USA)
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Publications (101)
Different types of gold nanoparticles have been synthesized that show great potential in medical applications such as medical imaging, bio-analytical sensing and photothermal cancer therapy. However, their stability, polydispersity and biocompatibility are major issues of concern. For example, the synthesis of gold nanorods, obtained through the el...
Dental restoration materials are susceptible to bacterial biofilm formation, which damages the restorations and causes oral health problems. Therefore, to overcome this, silver nanoparticles (AgNPs) are studied widely due to their antimicrobial, anti-inflammatory and healing properties. The purpose of this study was to develop a strategy for incorp...
We report here the spontaneous formation of lipid-bilayer-wrapped virus particles, following the injection of “naked” virus particles into the subphase of a Langmuir trough with a liquid monolayer of lipids at its air–water interface. The virus particles are those of the well-studied cowpea chlorotic mottle virus, CCMV, which are negatively charged...
Cowpea chlorotic mottle virus (CCMV) and brome mosaic virus (BMV) are naked plant viruses with similar characteristics; both form a T = 3 icosahedral protein capsid and are members of the bromoviridae family. It is well known that these viruses completely disassemble and liberate their genome at a pH around 7.2 and 1 M ionic strength. However, the...
Although silver nanoparticles (AgNPs) are excellent antimicrobial agents, they are considered hazardous materials due to their cytotoxic effects. In this research, AgNPs were deposited on TiO2 using a natural flavonoid under neutral conditions (pH 7) to obtain antibacterial nanomaterials without cytotoxicity. First, AgNPs were synthesized using two...
The effect of polyvalent cations, like spermine, on the condensation of DNA into very well-defined toroidal shapes has been well studied and understood. A great effort has been made to obtain similar condensed structures from RNA molecules, but so far, it has been elusive. In this work, we show that single-stranded RNA (ssRNA) molecules can easily...
The oil industry has been focused on bitumens and heavy oils due to the depletion of petroleum reservoirs. For this reason, we studied the interfacial behavior comparison of films of bitumen and their asphaltene and maltene fractions by means of the Langmuir balance and Brewster angle microscopy at the air-water interface. The films were transferre...
The vast majority of plant viruses are unenveloped, i.e., they lack a lipid bilayer that is characteristic of most animal viruses. The interactions between plant viruses, and between viruses and surfaces, properties that are essential for understanding their infectivity and to their use as bionanomaterials, are largely controlled by their surface c...
The white spot syndrome virus (WSSV), currently affecting cultured shrimp, causes substantial economic losses to the worldwide shrimp industry. An antiviral therapy using double-stranded RNA interference (dsRNAi) by intramuscular injection (IM) has proven the most effective shrimp protection against WSSV. However, IM treatment is still not viable f...
One of the main known effects of cholesterol is to rigidify the cell membrane throughout the so-called condensing effect. Although many studies have been done in mixtures of cholesterol with different membrane lipids, there are not many studies in a wide concentration range of cholesterol or at physiological conditions. In this work, we studied mix...
Fluorescence Resonance Energy Transfer (FRET) is a high resolution technique that allows the characterization of spatial and temporal properties of biological structures and mechanisms. In the present work, we developed an in silico single-molecule FRET methodology to study the dynamics of fluorophores inside lipid rafts. We monitored the fluoresce...
The effect of polyvalent molecular cations, such as spermine, on the condensation of DNA into very well-defined toroidal shapes have been well studied and understood. However, a great effort has been made trying to obtain similar condensed structures from either ssRNA or dsRNA, which the latter carries similar negative charge density as dsDNA, alth...
One of the main known effects of cholesterol is to rigidify the cell membrane throughout the so-called condensing effect. Although many studies have been done in mixtures of cholesterol with different membrane lipids, there are not many studies in a wide concentration range of cholesterol or at physiological conditions. In this work, we studied mix...
Conocer las características fisicoquímicas de los elementos es muy importante, ya que éstas nos permiten estudiar sus propiedades, analizar su comportamiento y hasta sintetizar nuevos elementos. En este sentido, este trabajo pretende explorar, de un modo sencillo y didáctico, la estructura de la tabla periódica, la manera de interpretarla y cómo en...
We study the aggregation of charged ellipsoidal colloidal particles at the air/water interface. The particles diffuse on the interface and aggregate over time to form fractal structures. We found that the directionality of the interactions depends on the aspect ratio of the particles. For the smaller aspect ratio, the interaction is stronger along...
We present a study on the DLCA aggregation of charged ellipsoidal colloidal particles, with different aspect ratios, at the air/water interface. The particles di�use on the interface and aggregate over time to form fractal structures. The aggregation is due to attractive capillary interactions and we found that the directionality of the interaction...
The aim of this study was to investigate the factors that govern the activity and selectivity of two potent antimicrobial peptides (AMPs) using lipid membrane models of bacterial, erythrocyte and fungal cells. These models were used in calcein liposome leakage experiments to explore peptide efficiency. The AMPs (Pin2 and its variant Pin2[GVG]) show...
The aim of this study was to investigate the factors that govern the activity and selectivity of two potent antimicrobial peptides (AMPs) using lipid membrane models of bacterial, erythrocyte and fungal cells. These models were used in calcein liposome leakage experiments to explore peptide efficiency. The AMPs (Pin2 and its variant Pin2[GVG]) show...
Virus-like particles (VLPs) are being used for therapeutic developments such as vaccines and drug nanocarriers. Among these, plant virus capsids are gaining interest for the formation of VLPs because they can be safely handled and are noncytotoxic. A paradigm in virology, however, is that plant viruses cannot transfect and deliver directly their ge...
We present a combined experimental and theoretical study dedicated to analyze the variations in the surface chemistry of low hydroxylated multiwalled carbon nanotubes (MWCNT’s), so called nanotubols, when exposed to...
Alzheimer’s disease is the main cause of dementia and the deposition of amyloid beta peptide (Aβ) in the brain is the key event in its progression. Soluble oligomers of Aβ are proposed to be the primary neurotoxic agents, and prevention of Aβ self-assembly has been proposed as a therapeutic approach. To analyze the role of key amino acids for Aβ ag...
Different types of gold nanoparticles have been synthesized that great potential in medical applications such as medical imaging, bio-analytical sensing and photothermal therapy. However, their stability, polydispersity and biocompatibility are major issues of concern. For example, the synthesis of gold nanorods, obtained through the elongated mice...
A biofilm is a very complex consortium formed by a mix of different microorganisms, which have become an important health problem, because its formation is a resistance mechanism used by bacteria against antibiotics or the immune system. In this work, we show differences between some physicochemical properties of biofilms in mono- and multi-species...
The design and construction of novel nanocarriers that have controlled shape and size and are made of inherently biocompatible components represents a milestone in the field of nanomedicine. Here, we show the tailoring of nanoliposphere-like particles for use as biocompatible drug nanocarriers. They are made with the building block components prese...
Antioxidant, anticarcinogenic, and antimicrobial properties have been reported for ferulic acid (FA), therefore, its application interests both food and agriculture research. FA was immobilized in different chitosan (CS) matrices, physicochemicaly characterized and the effect on Aspergillus parasiticus ecological parameters evaluated. Nanoparticles...
The current methods for preparing gold nanoshells (AuNSs) produce shells with a diameter of approximately 40 nm or larger, with a relatively large polydispersity. However, AuNSs with smaller diameter and more monodisperse are better suited for biomedical applications. In this work, we present a modified method for the preparation of AuNSs, based on...
The assembly of most single-stranded RNA (ssRNA) viruses into icosahedral nucleocapsids is a spontaneous process driven by protein-protein and RNA-protein interactions. The precise nature of these interactions results in the assembly of extremely monodisperse and structurally indistinguishable nucleocapsids. In this work, by using a ssRNA plant vir...
The effects of visible light on biological systems have been widely studied. In particular, the alterations of blue light on the ocular lens have recently attracted much attention. Here, we present a study about the effects produced by green and red light on two different proteins: βL-crystallin and ovalbumin.
The effects of visible light on biological systems have been widely studied. In particular, the alterations
of blue light on the ocular lens have recently attracted much attention. Here, we present a study about
the effects produced by green and red light on two different proteins: βL-crystallin and ovalbumin.
Based on differential scanning calorim...
The effects of visible light on biological systems have been widely studied. In particular, the alterations of blue light on the ocular lens have recently attracted much attention. Here, we present a study about the effects produced by green and red light on two different proteins: βL-crystallin and ovalbumin. Based on differential scanning calorim...
Porcine reproductive and respiratory syndrome virus (PRRSV) significantly affects the swine industry worldwide. An efficient, protective vaccine is still lacking. Here, we report for the first time the generation and purification of PRRSV virus like particles (VLPs) by expressing GP5, M and N genes in Nicotiana silvestris plants. The particles were...
Download the article at: http://nar.oxfordjournals.org/content/early/2014/11/26/nar.gku1249.abstract
RNA molecules play different roles in coding, decoding and gene expression regulation. Such roles are often associated to the RNA secondary or tertiary structures. The folding dynamics lead to multiple secondary structures of long RNA molecules, si...
We present a combined experimental and theoretical study to analyze the structure, electronic properties, and aggregation behavior of hydroxylated multiwalled carbon nanotubes (OH–MWCNT). Our MWCNTs have average diameters of ∼2 nm, lengths of approximately 100–300 nm, and a hydroxyl surface coverage θ∼0.1. When deposited on the air/water interface...
The self-assembly of many viral capsids is dominated by protein-protein electrostatic interactions. To have a better understanding of this process, it is important to know how the protein and the capsid surface charges vary as a function of the pH and ionic strength. In this work, using phase analysis light scattering, we measured the electrophoret...
La dinámica de ensamblado del Cowpea Clorothic Mottle Virus (CCMV) y los diferentes tipos de arquitecturas, pueden ser logradas variando las condiciones de ensamble. El entendimiento de estos sistemas se ha logrado mediante mutaciones en las
subunidades proteicas y su análisis de ensamblaje in vitro. Basado en la estructura cristalina del CCMV obte...
Viral proteins cages provide platforms for modification of ligands [1]. The icosahedral viral protein capsid of Cowpea chlorotic mottle virus (CCMV) assembles from 180 identical protein subunits [2]. Each subunit presents multiple surface exposed functional groups that can be chemical modified to provide engineered site specific functional groups [...
Amaranth seeds are one of the most promising food ingredients, due to their high protein content, among which the most important are storage proteins known as globulins. However, little is known about the physicochemical of the globulin proteins. In this work, we study the physicochemical behavior of films made of amaranth 7S globulin and its inter...
Organizing carbon nanotubes into true monolayer structures is highly desirable, but this has been difficult due to their low solubility and tendency to aggregate. Here, we introduce a novel procedure to fabricate monolayers of nitrogen-doped carbon nanotubes (CNx) using a Langmuir trough. Doped nanotubes disperse well in the subphase and slowly get...
Langmuir films of globulin 11S protein, l-dipalmitoylphosphatidylcholine (L-DPPC), and mixtures of both on water and on buffer subphases were studied. Brewster angle microscopy (BAM) was used to characterize in situ the films morphology along Pi-A isotherms at the air/liquid interface. The L-DPPC monolayer on water behaved as has been reported exte...
In this work we have investigated the influence of NaCl on the adsorption of the antimicrobial cationic peptide bactenecin in the monolayer of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) at the air-water interface, as a function of NaCl concentrations in the subphase. We show that the effect of the salt concentration on DPPC monolayers is a...
We present an experimental study of the self-assembly of capsid proteins of the cowpea chlorotic mosaic virus (CCMV), in the absence of the viral genome, as a function of pH and ionic strength. In accord with previous measurements, a wide range of polymorphs can be identified by electron microscopy, among them single and multiwalled shells and tube...
Tracking single and multiple particles is of great importance for many physical investigations in a variety of different areas. It is essential to find and eliminate sources of systematic errors in the particle position determination (PPD) and to determine the limits of its applicability to a given problem. Particularly when measuring the interacti...
A soft method for purifying multi-wall carbon nanotubes (N-doped and undoped) is presented. The technique includes a hydrothermal/ultrasonic treatment of the material in conjunction with other subsequent treatments, including the extraction of polyaromatic compounds, dissolution of metal particles, bundle exfoliation, and uniform dispersion. This m...
In the last decade, there have been experimental reports on the formation of colloidal mesostructures at the air/water interface. These patterns, range from the formation of transient colloidal chains and soap‐froth structures that evolve to more energetically stable colloidal clusters. If the surface
colloidal density is high, a crystalline‐like...
We report the effect of N-nitrosodiethylamine (NDA) on the interaction between bovine serum albumin (BSA) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine monolayers (DPPC) at the air-water interface. We prepared aqueous solutions of NDA/BSA complexes maintaining a constant concentration of BSA of 1.49 x 10(-9) M and using NDA concentrations to obta...
Many potential applications have been proposed for carbon nanotubes, however, there is a lack of methods that can assemble this 1D building block into well ordered thin films. Here, we report a study on the surface-induced thin film assemblies of single-wall carbon nanotubes
(SWCNTs) functionalized with poly(styrene-4-sulfonic acid sodium salt)
(PS...
The interfacial behavior of asphaltene samples, obtained from two different sources, was studied by means of Langmuir balance and Brewster angle microscopy (BAM) at the air/water interface. Transferred films from the air/water interface on mica were studied by atomic force microscopy (AFM). Isotherms obtained from the Langmuir balance experiments f...
We have successfully coated CNTs with either positively or negatively charged polyelectrolytes employing Van der Waals interactions between nanotubes and polyelectrolyte molecules, without any previous chemical modification of the nanotubes walls. Polymer adsorption of polyelectrolytes was performed in an ethanolic solution, followed by redispersio...
The Langmuir and Langmuir-Blodgett (LB) techniques have been applied in a novel approach to build structurally well-ordered, oriented, and organized assemblies of water-soluble single-wall carbon nanotubes (ws-SWCNTs) at the air/water and air/solid interfaces. The SWCNTs were rendered hydrophilic by complexing them with a quenched polyelectrolyte....
The phase diagram of a two-dimensional model system for colloidal particles at the air-water interface was determined using Monte Carlo computer simulations in the isothermic-isobaric ensemble. The micrometer-range binary colloidal interaction has been modeled by hard disklike particles interacting via a secondary minimum followed by a weaker longe...
We report isotherm, Brewster angle (BAM), ellipsometry and atomic force microscopy (AFM) studies of Langmuir films of cholesterol. At low surface pressures the Langmuir monolayers of cholesterol show a gas(G)-liquid condensed (LC) coexistence region in the range of 10 to 40 *C. On further compression, the pure untilted LC phase region is entered, d...
In the past few years, measurements of the pair interaction potential have shown evidence of micrometer-range attractive interactions between colloidal particles trapped between glass plates. In these experiments it is believed that the glass walls play an important role in the observed attractions. Colloidal particles trapped at the air/water inte...
The surface-pressure-induced layering transition of a 2D nematic-like cyclolinear polyorganosiloxane that consists of six-membered rings of silicon and oxygen joined by oxygen bridges and that has phenyl side groups (CL-PMPhSi) is observed and characterized by film balance measurements, Brewster angle microscopy (BAM), and grazing incidence X-ray d...
We report isotherm and atomic force microscopy studies of collapsed Langmuir monolayers of fatty acids. The Langmuir monolayers were overcompressed in the range 7–40 °C and transferred onto mica after the sharp pressure drop when the collapse pressure was reached. Collapsed material was observed by AFM, which revealed that the multilayers are indee...
In this work, we present a methodology for choosing the best experimental conditions for transferring protein Langmuir films onto solid substrates. As an example of applying the proposed methodology, we used monolayers of the protein bovine serum albumin, which is a very stable protein and is of great interest in the development of immunosensors. L...
Siloxane polymers self-organized into nanostructures with controllable distinct thicknesses from 1 to at least 6 molecular layers, ie, 1-6 nm, are investigated. Macroscopic manipulation of the surface pressure for these ultrathin films leads to an architecture with a distinct layer thickness and a highly ordered structure as demonstrated by synchro...
We have studied monolayers of apolipoproteins CI and AII at the air/water interface, observing them along their isothermal compression processes with Brewster angle microscopy and using grazing incidence X-ray diffraction. The lateral order in Langmuir−Blodgett transferred proteins was also studied using atomic force microscopy (AFM). Previous stud...