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Gel and Film Composites of Silver Nanoparticles in κ-, ι-, and λ-Carrageenans: One-Pot Synthesis, Characterization, and Bioactivities

DOI:10.1007/s12668-020-00806-1
Authors:
Jose Paolo O. Bantang
Jose Paolo O. Bantang
Jose Paolo O. Bantang
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Ursela G. Bigol
Ursela G. Bigol
Ursela G. Bigol
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Drexel H Camacho at De La Salle University
Drexel H Camacho
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Abstract and Figures

Gel and film composites containing silver nanoparticles (AgNPs) were biosynthesized using carrageenan as the reducing agent, capping biomolecule, and polymer matrix in one-pot method. A comparison between the in situ syntheses of AgNPs was made between κ-, ι-, and λ-carrageenans. The structure and morphology of AgNPs in the composite were investigated using UV-visible and infrared spectroscopies, scanning and transmission electron microscopies, and thermal gravimetric analysis. The antimicrobial properties were also evaluated. Results showed that AgNPs fabrication was influenced by the carrageenan type, incubation temperature, and carrageenan concentration. High incubation temperature promoted the reduction of AgNPs. κ-Carrageenan showed stronger reduction capabilities of Ag⁺ than the other carrageenan types. Gel and film formabilities were also observed to be superior in κ-carrageenan than in the ι-, and λ- types. Higher concentrations (1%) of carrageenans promoted more Ag⁺ reduction and less aggregation of AgNPs. The formation of AgNPs was found to be independent of initial Ag⁺ concentration and that excess Ag⁺ ions are still present in the solution allowing for the formation of stable gel and free-standing film for κ-carrageenan compared with the ι-, and λ-carrageenans incorporating the AgNPs in the composite matrix. Microbial activities show that solutions of carrageenan/AgNP/Ag⁺ are active against bacteria and fungi. Gel and film forms of κ-carrageenan/AgNP/Ag⁺ are also active against bacteria.
a Chemical structures of κ-, ι-, and λ-carrageenans; b schematic diagram illustrating the interaction of AgNP with κ-carrageenan
a Chemical structures of κ-, ι-, and λ-carrageenans; b schematic diagram illustrating the interaction of AgNP with κ-carrageenan
… 
UV-Vis spectra of carrageenan/AgNP/Ag⁺ solution prepared at different temperatures using 0.1% w/v carrageenan and 50 mM [Ag⁺] in (a) κ-carrageenan, diluted solution; (b) ι-carrageenan, as-is solution; and (c) λ-carrageenan, as-is solution. Inset shows digital images of the solution, inset in (a) also shows the UV-Vis spectrum of undiluted solution prepared as-is at 60 °C. (d) Digital images of air-dried carrageenan/AgNP/Ag⁺ composite films in increasing concentrations of κ-, ι-, and λ-carrageenans prepared at 60 °C using 50 mM [Ag⁺]; (e–g) UV-Vis spectra of carrageenan/AgNP/Ag⁺ solution prepared at 60 °C and 50 mM [Ag⁺] in various concentrations (w/v) of (e) κ-carrageenan, diluted solution (1 mL aliquot diluted to 25 mL); (f) ι-carrageenan, as-is solution; and (g) λ-carrageenan as-is solution. Inset: top images of carrageenan/AgNP/Ag⁺ solutions; (h) UV-Vis spectra of κ-carrageenan/AgNP/Ag⁺ solution prepared at 60 °C using κ-carrageenan (1.0% w/v) at different Ag⁺ initial concentrations
UV-Vis spectra of carrageenan/AgNP/Ag⁺ solution prepared at different temperatures using 0.1% w/v carrageenan and 50 mM [Ag⁺] in (a) κ-carrageenan, diluted solution; (b) ι-carrageenan, as-is solution; and (c) λ-carrageenan, as-is solution. Inset shows digital images of the solution, inset in (a) also shows the UV-Vis spectrum of undiluted solution prepared as-is at 60 °C. (d) Digital images of air-dried carrageenan/AgNP/Ag⁺ composite films in increasing concentrations of κ-, ι-, and λ-carrageenans prepared at 60 °C using 50 mM [Ag⁺]; (e–g) UV-Vis spectra of carrageenan/AgNP/Ag⁺ solution prepared at 60 °C and 50 mM [Ag⁺] in various concentrations (w/v) of (e) κ-carrageenan, diluted solution (1 mL aliquot diluted to 25 mL); (f) ι-carrageenan, as-is solution; and (g) λ-carrageenan as-is solution. Inset: top images of carrageenan/AgNP/Ag⁺ solutions; (h) UV-Vis spectra of κ-carrageenan/AgNP/Ag⁺ solution prepared at 60 °C using κ-carrageenan (1.0% w/v) at different Ag⁺ initial concentrations
… 
SEM images of pure and AgNP composite films of κ-, ι-, and λ-carrageenans. Percentage of concentration is expressed in w/v of carrageenan in water. Composite films were prepared using 50 nM Ag⁺ at 60 °C
SEM images of pure and AgNP composite films of κ-, ι-, and λ-carrageenans. Percentage of concentration is expressed in w/v of carrageenan in water. Composite films were prepared using 50 nM Ag⁺ at 60 °C
… 
Particle size distribution and TEM images of AgNPs prepared at 60 °C using 1.0% w/v of (a) κ-carrageenan in 50 mM Ag⁺, (b) ι-carrageenan in 50 mM Ag⁺, (c) λ-carrageenan in 50 mM Ag⁺, (d) κ-carrageenan in 30 mM Ag⁺, and (e) κ-carrageenan in 10 mM Ag⁺
Particle size distribution and TEM images of AgNPs prepared at 60 °C using 1.0% w/v of (a) κ-carrageenan in 50 mM Ag⁺, (b) ι-carrageenan in 50 mM Ag⁺, (c) λ-carrageenan in 50 mM Ag⁺, (d) κ-carrageenan in 30 mM Ag⁺, and (e) κ-carrageenan in 10 mM Ag⁺
… 
FTIR spectra of carrageenans with and without AgNPs (a) κ-carrageenan, (b) ι-carrageenan, and (c) λ-carrageenan
+4
FTIR spectra of carrageenans with and without AgNPs (a) κ-carrageenan, (b) ι-carrageenan, and (c) λ-carrageenan
… 
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Gel and Film Composites of Silver Nanoparticles in κ-, ι-,
and λ-Carrageenans: One-Pot Synthesis,
Characterization, and Bioactivities
Jose Paolo O. Bantang
1
&Ursela G. Bigol
2
&Drexel H. Camacho
1
Accepted: 28 October 2020
#Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract
Gel and film composites containing silver nanoparticles (AgNPs) were biosynthesized using carrageenan as the reducing agent,
capping biomolecule, and polymer matrix in one-pot method. A comparison between the in situ syntheses of AgNPs was made
between κ-, ι-, and λ-carrageenans. The structure and morphology of AgNPs in the composite were investigated using UV-
visible and infrared spectroscopies, scanning and transmission electron microscopies, and thermal gravimetric analysis. The
antimicrobial properties were also evaluated. Results showed that AgNPs fabrication was influenced by the carrageenan
type, incubation temperature, and carrageenan concentration. High incubation temperature promoted the reduction of
AgNPs. κ-Carrageenan showed stronger reduction capabilities of Ag
+
than the other carrageenan types. Gel and film
formabilities were also observed to be superior in κ-carrageenan than in the ι-, and λ- types. Higher concentrations (1%)
of carrageenans promoted more Ag
+
reduction and less aggregation of AgNPs. The formation of AgNPs was found to be
independent of initial Ag
+
concentration and that excess Ag
+
ions are still present in the solution allowing for the formation
of stable gel and free-standing film for κ-carrageenan compared with the ι-, and λ-carrageenans incorporating the AgNPs in
the composite matrix. Microbial activities show that solutions of carrageenan/AgNP/Ag
+
are active against bacteria and
fungi. Gel and film forms of κ-carrageenan/AgNP/Ag
+
are also active against bacteria.
Keywords Carrageenan .Silver nanoparticles .Film composite .Antimicrobial
1 Introduction
Bionanocomposites are a class of composite materials that
contains components from a biological origin (such as
biopolymers) infused with nanoparticles. Interests in stud-
ies related to these classes of nanocomposite materials are
driven by its innate properties such as biocompatibility
and biodegradability [1]. It has been used in various ap-
plications such as water purification, catalysis, medicine,
pharmaceutics, cosmetics, food packaging, agriculture,
sensors, and electronics [2–4].
Biopolymers such as proteins and polysaccharides are typ-
ically used as matrix for bionanocomposites. Polysaccharides
are a class of hydrocolloid biopolymers composed of repeat-
ing monomeric carbohydrate units (such as glucose, galactose,
and mannose). These carbohydrate polymers are abundant in
nature and can be obtained from various sources such as plants
and marine organisms. Some common examples of polysac-
charides are cellulose, chitin, chitosan, alginate, carrageenan,
and their corresponding derivatives. In general, the structure
of polysaccharides is rich with polar hydroxyl groups, and
some possess innate charged functional groups. For instance,
chitosan is positively charged in acidic medium due to the
presence of protonated amine groups. Algal polysaccharides
such as carrageenans and alginate are negatively charged at-
tributed to the sulfate groups and carboxylate groups, respec-
tively [5]. Due to the presence of hydroxyl groups and other
charged functional groups, polysaccharides and other
Highlights
•Facile in situ formation of AgNP in κ-, ι-, and λ-carrageenan matrices
•Carrageenan/AgNP/Ag
+
composite forms gel and film increasing its
utility.
•The gel and film composites are bioactive against microbes and fungi.
*Drexel H. Camacho
drexel.camacho@dlsu.edu.ph
1
Chemistry Department, De La Salle University, 2401 Taft Avenue,
0922 Manila, Philippines
2
Department of Science and Technology, Industrial Technology
Development Institute, DOST Compound, General Santos Avenue,
Bicutan, Taguig City, Philippines
https://doi.org/10.1007/s12668-020-00806-1
/ Published online: 10 November 2020
BioNanoScience (2021) 11:53–66
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
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