Exploration of Nanosilver Calcium Alginate-Based Multifunctional Polymer Wafers for Wound Healing

Abstract

Wound care is an integral part of effective recovery. However, its associated financial burden on national health services globally is significant enough to warrant further research and development in this field. In this study, multifunctional polymer wafers were prepared, which provide antibacterial activity, high cell viability, high swelling capacity and a thermally stable medium which can be used to facilitate the delivery of therapeutic agents. The purpose of this polymer wafer is to facilitate wound healing, by creating nanosilver particles within the polymer matrix itself via a one-pot synthesis method. This study compares the use of two synthetic agents in tandem, detailing the effects on the morphology and size of nanosilver particles. Two synthetic methods with varying parameters were tested, with one method using silver nitrate, calcium chloride and sodium alginate, whilst the other included aloe vera gel as an extra component, which serves as another reductant for nanosilver synthesis. Both methods generated thermally stable alginate matrices with high degrees of swelling capacities (400-900%) coupled with interstitially formed nanosilver of varying shapes and sizes. These matrices exhibited controlled nanosilver release rates which were able to elicit antibacterial activity against MRSA, whilst maintaining an average cell viability value of above 90%. Based on the results of this study, the multifunctional polymer wafers that were created set the standard for future polymeric devices for wound healing. These polymer wafers can then be further modified to suit specific types of wounds, thereby allowing this multifunctional polymer wafer to be applied to different wounding scenarios.

Keywords: alginate; cross-linked; nanosilver; wound healing.

Figure 1

SEM analysis of NA samples (A) SEM images at ×200 magnification and (B) average pore size of samples with respect to increasing w/v ratio.

Figure 2

SEM analysis of NAA. (A) SEM images of 1% w/v samples at ×200 magnification, (B) SEM images of 5% w/v samples at ×200 magnification, (C) SEM images of 10% w/v samples at ×200 magnification and (D) average pore size of samples with respect to increasing stir time.

Figure 2

SEM analysis of NAA. (A) SEM images of 1% w/v samples at ×200 magnification, (B) SEM images of 5% w/v samples at ×200 magnification, (C) SEM images of 10% w/v samples at ×200 magnification and (D) average pore size of samples with respect to increasing stir time.

Figure 3

SEM images of silver nanoparticles created from: (A) NA 1–100%, (B) NAA 1% w/v, (C) NAA 5% w/v, and (D) NAA 10% w/v.

Figure 3

SEM images of silver nanoparticles created from: (A) NA 1–100%, (B) NAA 1% w/v, (C) NAA 5% w/v, and (D) NAA 10% w/v.

Figure 4

(A) Graph detailing the changes in particle size with respect to increasing alginate concentration. (B) Graph detailing the changes in particle size with respect to stirring time for NAA 1% w/v, (C) graph detailing the changes in particle size with respect to stirring time NAA 5% w/v, and (D) graph detailing the changes in particle size with respect to stirring time for NAA 10% w/v.

Figure 5

Graphs displaying the total amount of nanosilver released, which were measured at the 24 h time point for (A) NA samples and (B) NAA samples.

Figure 6

FTIR graphs for: (A) NA 1–10%, (B) 1% NAA 1–24 h, (C) 5% NAA 1–24 h and (D) 10% NAA 1–24 h.

Figure 7

Changes in swelling capacity for (A) NA samples and (B) NAA samples.

Figure 8

Evaporative water loss values for (A) NA samples and (B) NAA samples.

Figure 9

Graphs displaying the TGA and DSC analysis results for all experimental samples. (A) NA 1–10% DSC, (B) NAA 1% 1–24 h DSC, (C) NAA 5% 1–24 h DSC, (D) NAA 10% 1–24 h DSC, (E) NA 1–10% TGA, (F) NAA 1% 1–24 h TGA, (G) NAA 5% 1–24 h TGA and (H) NAA 10% 1–24 h TGA.

Figure 10

Zone of inhibition coupled with MTT. (A) NAA 1–7 h [MRSA], (B) NAA 9–24 + calcium alginate control [MRSA], (C) NAA% 1–7 h [E. coli], (D) NAA% 9–24 h + calcium alginate control [E. coli], (E) 1–10% NA + calcium alginate control [MRSA] and (F) 1–10% NA + calcium alginate control [E. coli].

Figure 11

Graphs displaying the relative zone of inhibitions sizes with respect to the sample disc size. (A) 1%, 5% and 10% w/v NAA samples, (B) 1–10% NA samples.

Figure 12

Graphs detailing average cell viability normalised against the control. (A) NAA samples and (B) NA samples.

Figure 13

Graphs detailing average cell viability with respect to nanosilver particle size. (A) NAA samples and (B) NA samples.

Figure 14

Light microscopy images at ×10 magnification detailing the HFF growth patterns. (A) Control with no alginate polymer and (B–D) average sample containing alginate polymer. The red rings highlight the anchor point between the cells and the polymer sample.