Advancements and future directions in the antibacterial wound dressings - A review.

Wound repair is a complex process that has not been entirely understood. It can conclude in several irregularities. Hence, designing an appropriate wound dressing that can accelerate the healing period is critical. Infections, a major obstacle to wound repair, cause an elevated inflammatory responses and result in ultimate outcome of incomplete and prolonged wound repair. To overcome these shortcomings, there is a growing requirement for antibacterial wound dressings. Dressings with antibacterial activities and multifunctional behaviors are highly anticipated to avoid the wound infection for successful healing. The aim of this review is not only to concentrate on the importance of antibacterial dressings for wound healing applications but also to discuss recent studies and some future perspectives about antibacterial wound dressings.

Evaluation of hyaluronic acid nanoparticle embedded chitosan-gelatin hydrogels for antibiotic release.

The development of chitosan-gelatin (CS-G) hydrogels embedded with ampicillin-loaded hyaluronic acid nanoparticles (HA-NPs) for wound dressing is proposed. It was aimed to provide controlled ampicillin delivery by incorporation of HA-NPs into biocompatible CS-G hydrogel structure. According to in vitro ampicillin release studies, 55% of ampicillin was released from CS-G/HA-NPs hydrogels after 5 days. Antibacterial performance of CS-G/HA-NPs hydrogels was proven with agar disc diffusion test. For cytotoxicity assay, fibroblast cell viability increased in CS-G/HA-NPs hydrogels compared with CS-G group after 24 hr incubation. Consequently, the potential ability of CS-G/HA-NPs hydrogels as a controlled drug delivery system has been verified.

Phenol removal from wastewater by surface imprinted bacterial cellulose nanofibres.

In this study, we have reported a novel wastewater treatment technique by phenol imprinted bacterial cellulose (BC-MIP) nanofibres with high specificity and adsorption capacity. N-methacryloyl-(L) phenylalanine methyl ester (MAPA) functional monomer was used to create specific binding sites for the template molecule phenol via electrostatic and hydrophobic interactions. BC-MIP nanofibres were synthesized by surface imprinting approach in the presence of different amounts of total monomer (% weight), monomer/template ratio and polymerization time. Then, the nanofibres were characterized by FTIR-ATR, surface area analysis (BET), elemental analysis, scanning electron microscopy (SEM) and contact angle measurements. Adsorption studies were performed with respect to pH, temperature and ionic strength, and the adsorption capacity was calculated by using the spectrophotometer. In order to desorb the adsorbed phenol from BC-MIP nanofibres, 0.1 M NaCl solution was used. Besides, BC-MIP nanofibres were applied to real wastewater samples from Ergene basin in Turkey. The suitable equilibrium isotherm was determined as Langmuir isotherm. To evaluate the selectivity of the BC-MIP nanofibres, similar molecules were utilized as competitor molecules, which were 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol. Electrostatic interactions were found to contribute to the generation of specific recognition binding sites. The results have shown that imprinting of phenol was achieved successfully with high adsorption capacity. The phenol removal efficiency was reported up to 97%. BC-MIP nanofibres were used 10 times with a negligible decrease in adsorption capacity.

Molecularly imprinted composite bacterial cellulose nanofibers for antibiotic release.

The aim of this work is to develop drug carrier system with high loading capacity and controlled drug release profile for antibiotic release. For this purpose, composite molecularly imprinted nanofibers were prepared via in-situ graft polymerization of methacrylic acid as a monomer, N,N'-methylene bisacrylamide as a crosslinker and gentamicin sulfate as a template molecule onto surface-modified bacterial cellulose nanofibers. Gentamicin imprinted microparticles were fabricated onto bacterial cellulose nanofibers resulting in the formation of composite BC nanofibers. Thus, the composite nanofibers incorporated with gentamicin imprinted microparticles were achieved to fabricated. The in-vitro drug release tests were performed to evaluate the release performance of the resultant composite nanofibers at 37 °C. Also, kinetic models were applied to the drug release data. It was determined that the drug release from the composite molecularly imprinted nanofibers fit well in the Korsmeyer-Peppas model.

Protein depletion with bacterial cellulose nanofibers.

In this study, we have reported a novel fabrication technique for human serum albumin (HSA) imprinted composite bacterial cellulose nanofibers (MIP-cBCNFs) used for the depletion of HSA selectively from artificial blood plasma for proteomic applications. Molecular imprinting was achieved by using metal ion coordination interactions of N­methacryloyl­(l)­histidinemethylester (MAH) monomer and Cu(II) ions. MAH-Cu(II)-HSA complex was polymerized with bacterial cellulose nanofibers (BCNFs) under constant stirring at room temperature. The characterization of the MIP-cBCNFs was carried out by FTIR-ATR, SEM, contact angle measurements and surface area measurements. The adsorption experiments of HSA onto the MIP-BCNFs and NIP-BCNFs from aqueous HSA solutions were investigated in a batch system. The selectivity of the MIP-cBCNFs was investigated by using non-template human transferrin (HTR), and myoglobin (Myo). The relative selectivity coefficients of the MIP-cBCNFs were calculated as 4.73 and 3.02 for HSA/HTR and HSA/Myo molecules, respectively. In addition, the depletion of HSA from artificial human plasma was confirmed by SDS-PAGE and 2-D gel electrophoresis. As a result, it has been shown that metal ion coordination interactions contribute to specific binding of template when preparing MIP-cBCNFs for the depletion of HSA with a high adsorption capacity, significant selectivity and reusability.

Recognition of lysozyme using surface imprinted bacterial cellulose nanofibers.

Here, we developed the lysozyme imprinted bacterial cellulose (Lyz-MIP/BC) nanofibers via the surface imprinting strategy that was designed to recognize lysozyme. This study includes the molecular imprinting method onto the surface of bacterial cellulose nanofibers in the presence of lysozyme by metal ion coordination, as well as further characterizations methods FTIR, SEM and contact angle measurements. The maximum lysozyme adsorption capacity of Lyz-MIP/BC nanofibers was found to be 71 mg/g. The Lyz-MIP/BC nanofibers showed high selectivity for lysozyme towards bovine serum albumin and cytochrome c. Overall, the Lyz-MIP/BC nanofibers hold great potential for lysozyme recognition due to the high binding capacity, significant selectivity and excellent reusability.

Surface imprinted bacterial cellulose nanofibers for hemoglobin purification.

There is a significant need for the development of the novel adsorbents in the field of protein purification. In this study, thin hemoglobin imprinted film (MIP) was fabricated onto the bacterial cellulose nanofibers' (BCNFs) by surface imprinting method using metal ion coordination interactions with N-methacryloyl-(L)-histidinemethylester (MAH) and copper ions. The hemoglobin surface imprinted bacterial cellulose nanofibers (MIP-BCNFs) was applied to selective recognition of hemoglobin and purification from hemolysate. The characterization of the MIP-BCNFs was carried out by the Fourier Transformed Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), micro-Computerized Tomography (µCT), atomic force microscopy (AFM) and surface area measurements. The adsorption experiments of hemoglobin onto the MIP-BCNFs and NIP-BCNFs from aqueous hemoglobin solutions were investigated in a batch system. The results showed that MIP-BCNFs are promising materials for purification of hemoglobin with high adsorption capacity, significant selectivity and reusability.

Affinity binding of proteins to the modified bacterial cellulose nanofibers.

The potential of the modified bacterial cellulose (BC) nanofibers was determined bearing metal ion coordination interactions to enhance the protein adsorption and binding capacity. Thus, a household synthesized metal chelating monomer, namely N-methacryloyl-l-histidine methylester (MAH), and a commercial metal chelating monomer, namely 4-vinylimidazole (VIm), were used to complex with metal ions Cu(II) and Ni(II) respectively for the synthesis of the modified BC nanofibers. The modified nanofibers were characterized by FT-IR, SEM and EDX measurements. The protein adsorption tests were carried out using hemoglobin as a model protein and it was determined that the maximum adsorption capacity of hemoglobin onto the modified BC nanofibers was found as 47.40mg/g. The novel strategy for the preparation of metal chelated nanofibers was developed.

Toward a Universal Method for Preparing Molecularly Imprinted Polymer Nanoparticles with Antibody-like Affinity for Proteins.

We describe a potentially universal, simple and cheap method to prepare water-compatible molecularly imprinted polymer nanoparticles (MIP-NPs) as synthetic antibodies against proteins. The strategy is based on a solid phase synthesis approach where glass beads (GBs) are functionalized with a metal chelate, acting as a general affinity ligand to attract surface-bound histidines present on proteins. This configuration enables an oriented immobilization of the proteins, upon which thermoresponsive MIP-NPs are synthesized. The GBs play the role of both a reactor and a separation column since, after synthesis, the MIP-NPs are released from the support by a simple temperature change, resulting in protein-free polymers. The resulting MIP-NPs are endowed with improved binding site homogeneity, since the binding sites have the same orientation. Moreover, they are stable (no aggregation) in a buffer solution for prolonged storage time and exhibit apparent dissociation constants in the nanomolar range, with little or no cross-reactivity toward other proteins.

Molecularly imprinted supermacroporous cryogels for cytochrome c recognition.

Molecular imprinting is an attractive biomimetic approach that creates specific recognition sites for the shape and functional group arrangement to template molecules. The purpose of this study is to prepare cytochrome c-imprinted poly(hydroxyethyl methacrylate) (PHEMA)-based supermacroporous cryogel which can be used for the separation of cytochrome c from protein mixtures. N-Methacryloyl-(L)-histidinemethylester (MAH) was used as the metal-coordinating monomer. In the first step, Cu(2+) was complexed with MAH, and the cytochrome c imprinted PHEMA (MIP) cryogel was prepared by free radical cryopolymerization initiated by N,N,N',N'-tetramethylene diamine at -12°C. After polymerization is completed, the template cytochrome c molecules were removed from the MIP cryogel using 0.5 M NaCl solution. The maximum cytochrome c binding amount was 126 mg/g polymer. Selective binding studies were performed in the presence of lysozyme and bovine serum albumin. The relative selectivity coefficients of MIP cryogel for cytochrome c/lysozyme and cytochrome c/bovine serum albumin were 1.7 and 5.2 times greater than those of the non-imprinted PHEMA cryogel, respectively. The selectivity of MIP cryogel for cytochrome c was also confirmed with fast protein liquid chromatography. The MIP cryogel could be used many times with no remarkable decrease in cytochrome c binding capacity.