Surface modification and evaluation of bacterial cellulose for drug delivery

Production, structure, and performance of guar gum based bacterial cellulose generated from soy sauce residue hydrolysate by in-situ fermentation

Guar gum based bacterial cellulose (GG-BC) was generated from the soy sauce residue hydrolysate by in-situ fermentation, and its structure and performance were learned systematically. The GG concentration of 0.2 % was most suitable for GG-BC production with the yield of 1.21 g/L. During the in-situ fermentation, GG was implanted into the nano network of BC and thus altered its microstructure and properties. According to the FT-IR and NMR results, GG-BC had similar functional group structure and cellulose structural framework to those of BC. The degree of polymerization (DP) of GG-BC was 526.32-832.16, which was higher than that (426.32) of BC. Also, the GG-BC with low GG addition (0.2 % and 0.4 %) had a higher crystallinity than BC. Moreover, the GG-BC had a better heat tolerance than BC based on its higher temperature reaching the maximum degradation rate. The GG-BC with suitable GG addition had better texture characteristics, UV barrier property, swelling rate, and antioxidant activity than those of BC, showing that the in-situ fermentation with GG addition could promote the performance of GG-BC. Overall, this study can provide an attractive technology for both solving the environmental issue brought by soy sauce residue and producing high value-added GG-BC with good performance efficiently.

Cellulose Based Nano-Scaffolds for Targeted Cancer Therapies: Current Status and Future Perspective

In the last few years, cellulose has garnered much interest for its application in drug delivery, especially in cancer therapy. It has special properties like biocompatibility, biodegradability, high porosity, and water permeability render it a good candidate for developing efficient carriers for anticancer agents. Cellulose based nanomaterials like cellulose nanofibers, bacterial cellulose, cellulose nanocrystals and microcrystalline cellulose as delivery vehicles for targeted drug delivery to cancer cells are reviewed. This review elaborates on the synthesis, functionalization, and application strategies of these nanocarriers, and shows how they facilitate to improve drug stability, bioavailability and targeted delivery to tumor sites. Their possibilities as a tool to overcome the limitations of conventional cancer therapeutics are also discussed. We also explore future directions for improving the efficacy of cellulose based carriers in cancer therapy.

Insights into bacterial cellulose for adsorption and sustained-release mechanism of flavors

The stabilities and sustained-release properties of citral are significant for foods. Herein, bacterial cellulose (BC) was innovatively reported for adsorption and sustained-release of citral via gas-phase adsorption technique, and the adsorption mechanism was disclosed. BC was prepared from tobacco stem waste extract (TSWE), and better adsorption capacity (124.98 mg/g) was obtained through response surface optimization. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Flourier transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) were utilized to verify the successful adsorption. Thermo-gravimetry (TG) analysis showed that the release of citral was delayed. Temperature responsiveness indicated the release of citral was controlled by internal diffusion. Density functional theory (DFT) calculations indicated the interactions between BC and citral was mainly composed of van der Waals forces and hydrogen bonds. BC-Citral also exhibited excellent antibacterial capability. This work provided a new approach for constructing controlled-release materials of citral, which offered good application prospects in food industry.

Drug release kinetics from in-situ modulated agar/chitosan-bacterial cellulose patches for differently soluble drugs

Bacterial cellulose (BC) stands out as a promising candidate for novel drug delivery systems due to its micro-mesoporous nanofibrous interconnected structure. However, its performance is limited by the burst release of hydrophilic drugs and lower incorporation of the less water-soluble or insoluble drugs. In this study, we explored its potential as a drug carrier for two distinct types of drugs: Diclofenac sodium and Simvastatin, representing water-soluble and water insoluble compounds, respectively. To tune the morphology and drug-BC interaction, agar and chitosan were introduced into the culture medium during BC synthesis for in-situ modification. These modulated BCs are characterized and further analyzed through drug release studies and mathematical modeling to understand the mechanisms and key factors controlling the drug release behavior. Incorporating agar and chitosan into the BC network results in changes to its microstructure and crystallinity, which in turn affects the overall swelling, drug loading and release properties. Our results revealed that the BC followed a first-order quasi-Fickian kinetics for water-soluble drug and non-Fickian release mechanism for water-insoluble drug. In contrast, agar-modulated BC (A-MBC) demonstrated a non-Fickian first-order diffusion kinetics, with slow release for water-soluble drug and sustained release for the water-insoluble drug due to the higher density which impedes drug release. Chitosan-modulated BC (C-MBC) exhibited non-Fickian first-order kinetics, with slower release for water soluble drug. Further, C-MBC exhibited extended release for water insoluble drug to over 14 days, following first-order kinetics for the first 12 h, then transitioning to zero-order kinetics with a Case II release mechanism, attributed to drug-matrix interactions. These findings successfully demonstrate the possibility to tailor BC thus the release kinetics for both water-soluble and less soluble or insoluble drugs.

Antimicrobial assay and controlled drug release studies with novel eugenol imprinted p(HEMA)-bacterial cellulose nanocomposite, designed for biomedical applications

In this study, a novel bio-composite material that allow sustained release of plant derived antimicrobial compound was developed for the biomedical applications to prevent the infections caused by microorganisms resistant to commercial antimicrobials agents. With this aim, bacterial cellulose (BC)-p(HEMA) nanocomposite film that imprinted with eugenol (EU) via metal chelated monomer, MAH was prepared. Firstly, characterization studies were utilized by FTIR, SEM and BET analysis. Then antimicrobial assays, drug release studies and in vitro cytotoxicity test were performed. A significant antimicrobial effect against both Gram (+) Staphylococcus aureus and Gram (-) Escherichia coli bacteria and a yeast Candida albicans were observed even in low exposure time periods. When antimicrobial effect of EU compared with commercially used agents, both antifungal and antibacterial activity of EU were found to be higher. Then, sustained drug release studies showed that approximately 55% of EU was released up to 50 h. This result proved the achievement of the molecular imprinting for an immobilization of molecules that desired to release on an area in a long-time interval. Finally, the in vitro cytotoxicity experiment performed with the mouse L929 cell line determined that the synthesized EU-imprinted BC nanocomposite was biocompatible.

Bacterial nanocellulose as a simple and tailorable platform for controlled drug release

In this study we present a proof of concept of a simple and straightforward approach for the development of a Bacterial Nanocellulose drug delivery system (BNC-DDS), envisioning the local delivery of immunomodulatory drugs to prevent foreign body reaction (FBR). Inspired by the self-adhesion behavior of BNC upon drying, we proposed a BNC laminate entrapping commercial crystalline drugs (dexamethasone-DEX and GW2580) in a sandwich system. The stability of the bilayer BNC-DDS was evidenced by the high interfacial energy of the bilayer films, 150 ± 11 and 88 ± 7 J/m2 respectively for 2 mm- and 10-mm thick films, corresponding to an increase of 7.5 and 4.4-fold comparatively to commercial tissue adhesives. In vitro release experiments unveiled the tunability of the bilayer BNC-DDS by showing extended drug release when thicker BNC membranes were used (from 16 to 47 days and from 35 to 132 days, for the bilayer-BNC entrapping DEX and GW2580, respectively). Mathematical modeling of the release data pointed to a diffusion-driven mechanism with non-fickian behavior. Overall, the results have demonstrated the potential of this simple approach for developing BNC-drug depots for localized and sustained release of therapeutic agents over adjustable timeframes.

Protein Immobilization on Bacterial Cellulose for Biomedical Application

New carriers for protein immobilization are objects of interest in various fields of biomedicine. Immobilization is a technique used to stabilize and provide physical support for biological micro- and macromolecules and whole cells. Special efforts have been made to develop new materials for protein immobilization that are non-toxic to both the body and the environment, inexpensive, readily available, and easy to modify. Currently, biodegradable and non-toxic polymers, including cellulose, are widely used for protein immobilization. Bacterial cellulose (BC) is a natural polymer with excellent biocompatibility, purity, high porosity, high water uptake capacity, non-immunogenicity, and ease of production and modification. BC is composed of glucose units and does not contain lignin or hemicellulose, which is an advantage allowing the avoidance of the chemical purification step before use. Recently, BC-protein composites have been developed as wound dressings, tissue engineering scaffolds, three-dimensional (3D) cell culture systems, drug delivery systems, and enzyme immobilization matrices. Proteins or peptides are often added to polymeric scaffolds to improve their biocompatibility and biological, physical-chemical, and mechanical properties. To broaden BC applications, various ex situ and in situ modifications of native BC are used to improve its properties for a specific application. In vivo studies showed that several BC-protein composites exhibited excellent biocompatibility, demonstrated prolonged treatment time, and increased the survival of animals. Today, there are several patents and commercial BC-based composites for wounds and vascular grafts. Therefore, further research on BC-protein composites has great prospects. This review focuses on the major advances in protein immobilization on BC for biomedical applications.

Postbiotics-peptidoglycan, lipoteichoic acid, exopolysaccharides, surface layer protein and pili proteins-Structure, activity in wounds and their delivery systems

Chronic wound healing is a pressing global public health concern. Abuse and drug resistance of antibiotics are the key problems in the treatment of chronic wounds at present. Postbiotics are a novel promising strategy. Previous studies have reported that postbiotics have a wide range of biological activities including antimicrobial, immunomodulatory, antioxidant and anti-inflammatory abilities. However, several aspects related to these postbiotic activities remain unexplored or poorly known. Therefore, this work aims to outline general aspects and emerging trends in the use of postbiotics for wound healing, such as the production, characterization, biological activities and delivery strategies of postbiotics. In this review, a comprehensive overview of the physiological activities and structures of postbiotic biomolecules that contribute to wound healing is provided, such as peptidoglycan, lipoteichoic acid, bacteriocins, exopolysaccharides, surface layer proteins, pili proteins, and secretory proteins (p40 and p75 proteins). Considering the presence of readily degradable components in postbiotics, potential natural polymer delivery materials and delivery systems are emphasized, followed by the potential applications and commercialization prospects of postbiotics. These findings suggest that the treatment of chronic wounds with postbiotic ingredients will help provide new insights into wound healing and better guidance for the development of postbiotic products.

Antibacterial and Antibiofilm Potential of Bacterial Cellulose Hydrogel Containing Vancomycin against Multidrug-Resistant Staphylococcus aureus and Staphylococcus epidermidis

The present study aimed to evaluate the in vitro antibacterial and antibiofilm activity of bacterial cellulose hydrogel produced by Zoogloea sp. (HYDROGEL) containing vancomycin (VAN) against bacterial strains that cause wound infections, such as multidrug-resistant (MDR) Staphylococcus aureus and Staphylococcus epidermidis. Initially, HYDROGEL was obtained from sugar cane molasses, and scanning electron microscopy (SEM) was performed to determine morphological characteristics. Then, VAN was incorporated into HYDROGEL (VAN-HYDROGEL). The antibacterial activity of VAN, HYDROGEL, and VAN-HYDROGEL was assessed using the broth microdilution method to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against methicillin-sensitive S. aureus (MSSA) ATCC 25923, methicillin-resistant S. aureus (MRSA) ATCC 33591, S. epidermidis INCQS 00016 (ATCC 12228), five clinical isolates of MRSA, and nine clinical isolates of methicillin-resistant S. epidermidis, following the Clinical and Laboratory Standards Institute (CLSI) guidelines. Additionally, the antibacterial activity of VAN, HYDROGEL, and VAN-HYDROGEL was studied using the time-kill assay. Subsequently, the antibiofilm activity of VAN, HYDROGEL, and VAN-HYDROGEL was evaluated using crystal violet and Congo red methods, as well as SEM analysis. VAN and VAN-HYDROGEL showed bacteriostatic and bactericidal activity against MRSA and methicillin-resistant S. epidermidis strains. HYDROGEL did not show any antibacterial activity. Analysis of the time-kill assay indicated that HYDROGEL maintained the antibacterial efficacy of VAN, highlighting its efficiency as a promising carrier. Regarding antibiofilm activity, VAN and HYDROGEL inhibited biofilm formation but did not demonstrate biofilm eradication activity against methicillin-resistant S. aureus and S. epidermidis strains. However, it was observed that the biofilm eradication potential of VAN was enhanced after incorporation into HYDROGEL, a result also proven through images obtained by SEM. From the methods carried out in this study, it was possible to observe that HYDROGEL preserved the antibacterial activity of vancomycin, aside from exhibiting antibiofilm activity and enhancing the antibiofilm effect of VAN. In conclusion, this study demonstrated the potential of HYDROGEL as a candidate and/or vehicle for antibiotics against MDR bacteria that cause wound infections.

[New Advances in the Application of Bacterial Cellulose Composite Materials in the Field of Bone Tissue Engineering]

Bacterial cellulose (BC) is a type of extracellular polymeric nanomaterial secreted by microorganisms over the course of their growth. It has gained significant attention in the field of bone tissue engineering due to its unique structure of three-dimensional fibrous network, excellent biocompatibility, biodegradability, and exceptional mechanical properties. Nevertheless, BC still has some weaknesses, including low osteogenic activity, a lack of antimicrobial properties, small pore size, issues with the degradation rate, and a mismatch in bone tissue regeneration, limiting its standalone use in the field of bone tissue engineering. Therefore, the modification of BC and the preparation of BC composite materials have become a recent research focus. Herein, we summarized the relationships between the production, modification, and bone repair applications of BC. We introduced the methods for the preparation and the modification of BC. Additionally, we elaborated on the new advances in the application of BC composite materials in the field of bone tissue engineering. We also highlighted the existing challenges and future prospects of BC composite materials.

Preparation and characterization of bacterial cellulose synthesized by kombucha from vinegar residue

Bacterial cellulose (BC) has been widely applied in various fields due to its excellent physicochemical properties, but its high production cost remains a challenge. Herein, the present study aimed to utilize the hydrolysate of vinegar residue (VR) as the only medium to realize the cost-effective production of BC. The BC production was optimized by the single-factor test. The treatment of 6 % VR concentration with 3 % acid concentration at 100 °C for 1.5 h and 96 U/mL of cellulase for 4 h at 50 °C obtained a maximum reducing sugar concentration of about 32 g/L. Additionally, the VR hydrolysate treated with 3 % active carbon (AC) at 40 °C for 0.5 h achieved a total phenol removal ratio of 86 %. The yield of BC reached 2.1 g/L under the optimum conditions, which was twice compared to the standard medium. The produced BC was characterized by SEM, FT-IR, XRD, and TGA analyses, and the results indicated that the BC prepared by AC-treated VR hydrolysate had higher fiber density, higher crystallinity, and good thermal stability. Furthermore, the regenerated BC (RBC) fibers with a tensile stress of 400 MPa were prepared successfully using AmimCl solution as a solvent by dry-wet-spinning method. Overall, the VR waste could be used as an alternative carbon source for the sustainable production of BC, which could be further applied to RBC fibers preparation.

Preparation of bacterial cellulose-based antibacterial membranes with prolonged release of drugs: Emphasis on the chemical structure of drugs

Bacterial cellulose (BC) based antibacterial membranes were synthesized, including BC-cefoperazone (BC-CEF) and BC-cefoperazone sodium (BC-CEF/Na). To examine the various drug loading processes, the structure, morphology, and physical-chemical characteristics of membranes were evaluated. Results demonstrated that both types of medicines were successfully absorbed into membranes, and membranes displayed identical morphology and FT-IR peaks. BC-CEF showed lower crystalline of XRD, which was likely caused by the combination of carboxyl and hydroxyl. However, there were no drug peaks seen in the membranes, indicating no alteration of ribbon crystallization of BC. Two types of antibacterial membranes have significantly distinct drug-loading traits and drug-releasing profiles. The drug loading rate of CEF (46.4 mg/g) was significantly greater than CEF/Na (30.3 mg/g). The cumulative drug-releasing profiles showed that only BC-CEF continues to release drugs for a lengthy period up to 48 h and exhibited good antimicrobial activity against S. aureus and E. coli until 48 h. The cytotoxicity assay demonstrated the great biocompatibility of all membranes. Findings indicated that BC-CEF has the potential use as a prolonged biocide in the biomedical. The idea that BC membranes can naturally incorporate the carboxyl groups from antibiotics is also innovative and can be useful in developing of drug delivery systems.

Advances in drug delivery applications of modified bacterial cellulose-based materials

Bacterial cellulose (BC) is generated by certain species of bacteria and comprises polysaccharides with unique physical, chemical, and mechanical characteristics. Due to its outstanding biocompatibility, high purity, excellent mechanical strength, high water absorption, and highly porous structure, bacterial cellulose has been recently investigated for biomedical application. However, the pure form of bacterial cellulose is hardly used as a biomedical material due to some of its inherent shortcomings. To extend its applications in drug delivery, modifications of native bacterial cellulose are widely used to improve its properties. Usually, bacterial cellulose modifications can be carried out by physical, chemical, and biological methods. In this review, a brief introduction to bacterial cellulose and its production and fabrication is first given, followed by up-to-date and in-depth discussions of modification. Finally, we focus on the potential applications of bacterial cellulose as a drug delivery system.

Reprocessing of side-streams towards obtaining valuable bacterial metabolites

Every year, all over the world, the industry generates huge amounts of residues. Side-streams are most often used as feed, landfilled, incinerated, or discharged into sewage. These disposal methods are far from perfect. Taking into account the composition of the side-streams, it seems that they should be used as raw materials for further processing, in accordance with the zero-waste policy and sustainable development. The article describes the latest achievements in biotechnology in the context of bacterial reprocessing of residues with the simultaneous acquisition of their metabolites. The article focuses on four metabolites - bacterial cellulose, propionic acid, vitamin B12 and PHAs. Taking into account global trends (e.g. food, packaging, medicine), it seems that in the near future there will be a sharp increase in demand for this type of compounds. In order for their production to be profitable and commercialised, cheap methods of its obtaining must be developed. The article, in addition to obtaining these bacterial metabolites from side-streams, also discusses e.g. factors affecting their production, metabolic pathways and potential and current applications. The presented chapters provide a complete overview of the current knowledge on above metabolites, which can be helpful for the academic and scientific communities and the several industries. KEY POINTS: • The industry generates millions of tons of organic side-streams each year. • Generated residues burden the natural environment. • A good and cost-effective method of side-streams management seems to be biotechnology - reprocessing with the use of bacteria. • Biotechnological disposal of side-streams gives the opportunity to obtain valuable compounds in cheaper ways: BC, PA, vitmain B12, PHAs.

Opportunities for bacterial nanocellulose in biomedical applications: Review on biosynthesis, modification and challenges

Bacterial nanocellulose (BNC) is a natural polysaccharide produced as extracellular material by bacterial strains and has favorable intrinsic properties for primary use in biomedical applications. In this review, an update on state-of-the art and challenges in BNC production, surface modification and biomedical application is given. Recent insights in biosynthesis allowed for better understanding of governing parameters improving production efficiency. In particular, introduction of different carbon/nitrogen sources from alternative feedstock and industrial upscaling of various production methods is challenging. It is important to have control on the morphology, porosity and forms of BNC depending on biosynthesis conditions, depending on selection of bacterial strains, reactor design, additives and culture conditions. The BNC is intrinsically characterized by high water absorption capacity, good thermal and mechanical stability, biocompatibility and biodegradability to certain extent. However, additional chemical and/or physical surface modifications are required to improve cell compatibility, protein interaction and antimicrobial properties. The novel trends in synthesis include the in-situ culturing of hybrid BNC nanocomposites in combination with organic material, inorganic material or extracellular components. In parallel with toxicity studies, the applications of BNC in wound care, tissue engineering, medical implants, drug delivery systems or carriers for bioactive compounds, and platforms for biosensors are highlighted.

Turmeric Herb Extract-Incorporated Biopolymer Dressings with Beneficial Antibacterial, Antioxidant and Anti-Inflammatory Properties for Wound Healing

Bacterial infection and inflammation caused by excess oxidative stress are serious challenges in chronic wound healing. The aim of this work is to investigate a wound dressing based on natural- and biowaste-derived biopolymers loaded with an herb extract that demonstrates antibacterial, antioxidant, and anti-inflammatory activities without using additional synthetic drugs. Turmeric extract-loaded carboxymethyl cellulose/silk sericin dressings were produced by esterification crosslinking with citric acid followed by freeze-drying to achieve an interconnected porous structure, sufficient mechanical properties, and hydrogel formation in situ in contact with an aqueous solution. The dressings exhibited inhibitory effects on the growth of bacterial strains that were related to the controlled release of the turmeric extract. The dressings provided antioxidant activity as a result of the radical scavenging effect on DPPH, ABTS, and FRAP radicals. To confirm their anti-inflammatory effects, the inhibition of nitric oxide production in activated RAW 264.7 macrophages was investigated. The findings suggested that the dressings could be a potential candidate for wound healing.

Nanocellulose-Based Adsorbents for Heavy Metal Ion

Heavy metal ions in industrial sewage constitute a serious threat to human health. Nanocellulose-based adsorbents are emerging as an environmentally friendly material platform for heavy metal ion removal based on their unique properties, which include high specific surface area, excellent mechanical properties, and biocompatibility. In this review, we cover the most recent works on nanocellulose-based adsorbents for heavy metal ion removal and present an in-depth discussion of the modification technologies for nanocellulose in the process of assembling high-performance heavy ion adsorbents. By introducing functional groups, such as amino, carboxyl, aldehyde, and thiol, the assembled nanocellulose-based adsorbents both remove single heavy metal ions and can selectively adsorb multiple heavy ions in water. Finally, the remaining challenges of nanocellulose-based adsorbents are pointed out. We anticipate that this review will provide indispensable guidance on the application of nanocellulose-based adsorbents for the removal of heavy metal ions.

Active Potential of Bacterial Cellulose-Based Wound Dressing: Analysis of Its Potential for Dermal Lesion Treatment

The use of innate products for the fast and efficient promotion of healing process has been one of the biomedical sector's main bets for lesion treatment modernization process. The aim of this study was to develop and characterize bacterial cellulose-based (BC) wound dressings incorporated with green and red propolis extract (2 to 4%) and the active compounds p-coumaric acid and biochanin A (8 to 16 mg). The characterization of the nine developed samples (one control and eight active wound dressings) evidenced that the mechanics, physics, morphological, and barrier properties depended not only on the type of active principle incorporated onto the cellulosic matrix, but also on its concentration. Of note were the results found for transparency (28.59-110.62T₆₀₀ mm^-1), thickness (0.023-0.046 mm), swelling index (48.93-405.55%), water vapor permeability rate (7.86-38.11 g m² day^-1), elongation (99.13-262.39%), and antioxidant capacity (21.23-86.76 μg mL^-1). The wound dressing based on BC and red propolis was the only one that presented antimicrobial activity. The permeation and retention test revealed that the wound dressing containing propolis extract presented the most corneal stratum when compared with viable skin. Overall, the developed wound dressing showed potential to be used for treatment against different types of dermal lesions, according to its determined proprieties.

Surface Modification of Bacterial Cellulose for Biomedical Applications

Bacterial cellulose is a naturally occurring polysaccharide with numerous biomedical applications that range from drug delivery platforms to tissue engineering strategies. BC possesses remarkable biocompatibility, microstructure, and mechanical properties that resemble native human tissues, making it suitable for the replacement of damaged or injured tissues. In this review, we will discuss the structure and mechanical properties of the BC and summarize the techniques used to characterize these properties. We will also discuss the functionalization of BC to yield nanocomposites and the surface modification of BC by plasma and irradiation-based methods to fabricate materials with improved functionalities such as bactericidal capabilities.

Recent Trends in Assessment of Cellulose Derivatives in Designing Novel and Nanoparticulate-Based Drug Delivery Systems for Improvement of Oral Health

Natural polymers are revolutionizing current pharmaceutical dosage forms design as excipient and gained huge importance because of significant influence in formulation development and drug delivery. Oral health refers to the health of the teeth, gums, and the entire oral-facial system that allows us to smile, speak, and chew. Since years, biopolymers stand out due to their biocompatibility, biodegradability, low toxicity, and stability. Polysaccharides such as cellulose and their derivatives possess properties like novel mechanical robustness and hydrophilicity that can be easily fabricated into controlled-release dosage forms. Cellulose attracts the dosage design attention because of constant drug release rate from the precursor nanoparticles. This review discusses the origin, extraction, preparation of cellulose derivatives and their use in formulation development of nanoparticles having multidisciplinary applications as pharmaceutical excipient and in drug delivery, as bacterial and plant cellulose have great potential for application in the biomedical area, including dentistry, protein and peptide delivery, colorectal cancer treatment, and in 3D printable dosage forms.

Membrane Technological Pathways and Inherent Structure of Bacterial Cellulose Composites for Drug Delivery

This report summarizes efforts undertaken in the area of drug delivery, with a look at further efforts made in the area of bacterial cellulose (BC) biomedical applications in general. There are many current methodologies (past and present) for the creation of BC membrane composites custom-engineered with drug delivery functionality, with brief consideration for very close applications within the broader category of biomedicine. The most emphasis was placed on the crucial aspects that open the door to the possibility of drug delivery or the potential for use as drug carriers. Additionally, consideration has been given to laboratory explorations as well as already established BC-drug delivery systems (DDS) that are either on the market commercially or have been patented in anticipation of future commercialization. The cellulose producing strains, current synthesis and growth pathways, critical aspects and intrinsic morphological features of BC were given maximum consideration, among other crucial aspects of BC DDS.

Multifunctional applications of natural polysaccharide starch and cellulose: An update on recent advances

The emergence of clinical complications and therapeutic challenges for treating various diseases necessitate the discovery of novel restorative functional materials. Polymer-based drug delivery systems have been extensively reported in the last two decades. Recently, there has been an increasing interest in the progression of natural biopolymers based controlled therapeutic strategies, especially in drug delivery and tissue engineering applications. However, the solubility and functionalisation due to their complex network structure and intramolecular bonding seem challenging. This review explores the current advancement and prospects of the most promising natural polymers such as cellulose, starch and their derivatives-based drug delivery vehicles like hydrogels, films and composites, in combating major ailments such as bone infections, microbial infections, and cancers. In addition, selective drug targeting using metal-drug (MD) and MD-based polymeric missiles have been exciting but challenging for its application in cancer therapeutics. Owing to high biocompatibility of starch and cellulose, these materials have been extensively evaluated in biomedical and pharmaceutical applications. This review presents a detailed impression of the current trends for the construction of biopolymer-based tissue engineering, drug/gene/protein delivery vehicles.

Comparison of drug release behavior of bacterial cellulose loaded with ibuprofen and propranolol hydrochloride

The aim of this study was to investigate the drug release behavior from bacterial cellulose (BC). Ibuprofen and propranolol hydrochloride were used as model drugs to represent low and highly water soluble drugs. The drug was loaded into the BC by immersing the partially swollen BC in a solution of drug concentrations ranging from 0.05 to 0.5 mg mL-1 and then drying by two different methods: air-drying and freeze-drying. The results showed that the type of drug and the drying method influenced the drug loading efficiency and drug release behavior. For ibuprofen, high drug loading efficiency was found when loading the drug into BC at low concentration and vice versa for propranolol hydrochloride. The drug-loaded BC prepared by the freeze-drying method showed a sustained release regardless of drug type and drug-loaded amount. The sustained release followed the Higuchi and Korsmeyer-Peppas models. On the other hand, when using the air-drying method, BC loaded with ibuprofen showed immediate release at every drug-loaded amount. However, BC loaded with propranolol hydrochloride showed immediate release at the high drug-loaded amount but showed sustained release at the low drug-loaded amount. The release of drug from a drug-loaded BC prepared by air-drying method tended to follow first-order kinetics. In conclusion, the drug loading concentration and the drying method in the drug-loaded BC preparation influenced the drug release characteristics of the BC-based drug delivery system.

Addition of Various Cellulosic Components to Bacterial Nanocellulose: A Comparison of Surface Qualities and Crystalline Properties

Bacterial nanocellulose (BNC) is a biocompatible material with a lot of potential. To make BNC commercially feasible, improvements in its production and surface qualities must be made. Here, we investigated the in situ fermentation and generation of BNC by addition of different cellulosic substrates such as Avicel and carboxymethylcellulose (CMC) and using Komagataeibacter sp. SFCB22-18. The addition of cellulosic substrates improved BNC production by a maximum of about 5 times and slightly modified its structural properties. The morphological and structural properties of BNC were investigated by using Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy and X-ray diffraction. Furthermore, a type-A cellulose-binding protein derived from Clostridium thermocellum, CtCBD3, was used in a novel biological analytic approach to measure the surface crystallinity of the BNC. Because Avicel and CMC may adhere to microfibrils during BNC synthesis or crystallization, cellulose-binding protein could be a useful tool for identifying the crystalline properties of BNC with high sensitivity.

Bacterial cellulose and its potential for biomedical applications

Bacterial cellulose (BC) is an important polysaccharide synthesized by some bacterial species under specific culture conditions, which presents several remarkable features such as microporosity, high water holding capacity, good mechanical properties and good biocompatibility, making it a potential biomaterial for medical applications. Since its discovery, BC has been used for wound dressing, drug delivery, artificial blood vessels, bone tissue engineering, and so forth. Additionally, BC can be simply manipulated to form its derivatives or composites with enhanced physicochemical and functional properties. Several polymers, carbon-based nanomaterials, and metal nanoparticles (NPs) have been introduced into BC by ex situ and in situ methods to design hybrid materials with enhanced functional properties. This review provides comprehensive knowledge and highlights recent advances in BC production strategies, its structural features, various in situ and ex situ modification techniques, and its potential for biomedical applications.

The Impact of the Mechanical Modification of Bacterial Cellulose Films on Selected Quality Parameters

This study investigated the effect of the homogenization of bacterial cellulose particles and their reintegration into a membrane on the mechanical and physical parameters of the films produced from them in relation to films made of native cellulose (not subjected to the homogenization process). Bacterial cellulose was obtained from a culture of microorganisms forming a conglomerate of bacteria and yeast, called SCOBY. The research has shown that the mechanical modification of bacterial cellulose contributes to an increase in the elongation of the material. Modified polymer films were characterized by a higher Young’s modulus and a much higher breaking force value compared to native cellulose. The mechanical modification of cellulose contributed to an increase in hygroscopicity and changes in water vapor permeability. The obtained results may provide significant information on the methods of modifying bacterial cellulose, depending on its various applications.

Production and Surface Modification of Cellulose Bioproducts

Petroleum-based synthetic plastics play an important role in our life. As the detrimental health and environmental effects of synthetic plastics continue to increase, the renewable, degradable and recyclable properties of cellulose make subsequent products the "preferred environmentally friendly" alternatives, with a small carbon footprint. Despite the fact that the bioplastic industry is growing rapidly with many innovative discoveries, cellulose-based bioproducts in their natural state face challenges in replacing synthetic plastics. These challenges include scalability issues, high cost of production, and most importantly, limited functionality of cellulosic materials. However, in order for cellulosic materials to be able to compete with synthetic plastics, they must possess properties adequate for the end use and meet performance expectations. In this regard, surface modification of pre-made cellulosic materials preserves the chemical profile of cellulose, its mechanical properties, and biodegradability, while diversifying its possible applications. The review covers numerous techniques for surface functionalization of materials prepared from cellulose such as plasma treatment, surface grafting (including RDRP methods), and chemical vapor and atomic layer deposition techniques. The review also highlights purposeful development of new cellulosic architectures and their utilization, with a specific focus on cellulosic hydrogels, aerogels, beads, membranes, and nanomaterials. The judicious choice of material architecture combined with a specific surface functionalization method will allow us to take full advantage of the polymer's biocompatibility and biodegradability and improve existing and target novel applications of cellulose, such as proteins and antibodies immobilization, enantiomers separation, and composites preparation.

Recent advancements in cellulose-based biomaterials for management of infected wounds

INTRODUCTION

Chronic wounds are a substantial burden on the healthcare system. Their treatment requires advanced dressings, which can provide a moist wound environment, prevent bacterial infiltration, and act as a drug carrier. Cellulose is biocompatible, biodegradable, and can be functionalized according to specific requirements, which makes it a highly versatile biomaterial. Antimicrobial cellulose dressings are proving to be highly effective against infected wounds.

AREAS COVERED

This review briefly addresses the mechanism of wound healing and its pathophysiology. It also discusses wound infections, biofilm formation, and progressive emergence of drug-resistant bacteria in chronic wounds and the treatment strategies for such types of infected wounds. It also summarizes the general properties, method of production, and types of cellulose wound dressings. It explores recent studies and advancements regarding the use of cellulose and its derivatives in wound management.

EXPERT OPINION

Cellulose and its various functionalized derivatives represent a promising choice of wound dressing material. Cellulose-based dressings loaded with antimicrobials are very useful in controlling infection in a chronic wound. Recent studies showing its efficacy against drug-resistant bacteria make it a favorable choice for chronic wound infections. Further research and large-scale clinical trials are required for better clinical evidence of its efficiency.

Simple conversion of 3D electrospun nanofibrous cellulose acetate into a mechanically robust nanocomposite cellulose/calcium scaffold

Cellulose and its derivatives are widely used as nanofibrous biomaterials, but obtaining 3D cellulose nanofibers is difficult and relevant research is scarce. In the present study, we propose a simple method for converting electrospun 3D cellulose acetate/lactic acid nanofibers via calcium hydroxide treatment into a 3D cellulose/calcium lactate nanocomposite matrix. The conversion resulted in producing a stronger nanofibrous matrix (1.382 MPa vs. 0.112 MPa) that is more hydrophilic and cell-friendly compared to the untreated cellulose acetate/lactic acid group. The successful conversion was verified via FTIR, XPS, TGA, DTG, and XRD. The ability of the scaffolds to provide a suitable environment for cell growth and infiltration was verified by CCK assay and confocal microscopy. The porous nature, mechanical strength, and presence of calcium make the 3D cellulose/calcium lactate matrix a promising material for bone tissue engineering.

Recent Advances and Applications of Bacterial Cellulose in Biomedicine

Bacterial cellulose (BC) is an extracellular polymer produced by Komagateibacter xylinus, which has been shown to possess a multitude of properties, which makes it innately useful as a next-generation biopolymer. The structure of BC is comprised of glucose monomer units polymerised by cellulose synthase in β-1-4 glucan chains which form uniaxially orientated BC fibril bundles which measure 3-8 nm in diameter. BC is chemically identical to vegetal cellulose. However, when BC is compared with other natural or synthetic analogues, it shows a much higher performance in biomedical applications, potable treatment, nano-filters and functional applications. The main reason for this superiority is due to the high level of chemical purity, nano-fibrillar matrix and crystallinity. Upon using BC as a carrier or scaffold with other materials, unique and novel characteristics can be observed, which are all relatable to the features of BC. These properties, which include high tensile strength, high water holding capabilities and microfibrillar matrices, coupled with the overall physicochemical assets of bacterial cellulose makes it an ideal candidate for further scientific research into biopolymer development. This review thoroughly explores several areas in which BC is being investigated, ranging from biomedical applications to electronic applications, with a focus on the use as a next-generation wound dressing. The purpose of this review is to consolidate and discuss the most recent advancements in the applications of bacterial cellulose, primarily in biomedicine, but also in biotechnology.

Development and Evaluation of Drug Loaded Regenerated Bacterial Cellulose-Based Matrices as a Potential Dosage Form

Bacterial cellulose (BC) is a highly pure form of cellulose and possesses superior physico-mechanical properties with wide range of applications. These properties of BC can further be improved by various modifications, including its regeneration from the BC solution. In the current research work, regenerated BC (R-BC) matrices were prepared using N-methyl-morpholine-oxide (NMMO; 50% w/w solution in water) and loaded with model drugs, i.e., famotidine or tizanidine. The characterization of drug loaded regenerated BC (R-BC-drug) matrices was carried out using Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA), which revealed the stability of matrices and successful drug loading. Results of dissolution studies showed immediate (i.e., >90%) drug release in 30 min. The drugs release data was found to best fit into first order kinetics model having R² values >0.99 for all the formulations. These results indicated that regenerated BC-based matrices had the ability to be used for delivery of orally administered drugs.

Overcoming the hydrophilicity of bacterial nanocellulose: Incorporation of the lipophilic coenzyme Q10 using lipid nanocarriers for dermal applications

Although used in a wide range of medical and pharmaceutical applications, the potential of the natural biopolymer bacterial nanocellulose (BNC) as drug delivery system is by far not fully exploited. Particularly, the incorporation of lipophilic drugs is still considered as an unsolved task. In the present study, the homogeneous incorporation of the lipophilic coenzyme Q10 (CoQ10) into BNC was accomplished by several post-synthesis techniques utilizing different nanoemulsions and liposomes. All colloidal carriers were in the range of about 90-120 nm with negative zeta potentials and storage stabilities up to 30 days. The biphasic drug release profiles of loaded BNC were found to be dependent on the type of colloidal carrier and the loading technique. Favorable characteristics such as high mechanical stability and high loading capacity were retained after the incorporation of the lipophilic components. Penetration studies using excised porcine skin revealed CoQ10 distributions also in deeper skin layers dependent on the type of the colloidal carrier system. In conclusion, hydrophilic BNC could be loaded with water-insoluble drugs as shown for the model drug CoQ10 by the use of lipidic colloidal carriers which offers new possibilities of application in pharmacy and medicine.

Biotech nanocellulose: A review on progress in product design and today's state of technical and medical applications

Biotech nanocellulose (bacterial nanocellulose, BNC) is a high potential natural polymer. Moreover, it is the only cellulose type that can be produced biotechnologically using microorganisms resulting in hydrogels with high purity, high mechanical strength and an interconnecting micropore system. Recently, the subject of intensive research is to influence this biosynthesis to create function-determining properties. This review reports on the progress in product design and today's state of technical and medical applications. A novel, dynamic, template-based technology, called Mobile Matrix Reservoir Technology (MMR Tech), is highlighted. Thereby, shape, dimensions, surface properties, and nanonetwork structures can be designed in a process-controlled manner. The formed multilayer materials open up new applications in medicine and technology. Especially medical materials for cardiovascular and visceral surgery, and drug delivery systems are developed. The effective production of layer-structured composites and coatings are important for potential applications in the electronics, paper, food and packaging technologies.

Development and characterization of bacterial nanocellulose loaded with Boswellia serrata extract containing nanoemulsions as natural dressing for skin diseases

The combination of the anti-inflammatory lipophilic Boswellia serrata extract with the natural hydropolymer bacterial nanocellulose (BNC) for the treatment of skin diseases is counteracted by their different hydro/lipophilicity. To overcome the hydrophilicity of the BNC, the water in its network was exchanged by single and double nanoemulsions. Incorporation of the Boswellia serrata extract in the nanoemulsions formed particles of about 115 to 150 nm with negative zeta potential and storage stability over 30 days at temperatures between 4 and 32 °C. Their loading into the BNC did not change the preferential characteristics of the nanocellulose like water absorption and retention, softness, and pressure stability in a relevant way. Loaded BNC could be sterilized by an electron-beam procedure. A biphasic drug release profile of lead compounds was observed by Franz cell diffusion test. The biocompatibility of the loaded BNC was confirmed ex ovo by a shell-less hen's egg test. Tape stripping experiments using porcine skin determined a dependency of the drug penetration into skin on the type of nanoemulsion, single vs. repeated applications and the incubation time. In conclusion, the hydrophilicity of BNC could be overcome using nanoemulsions which offers the possibility for the anti-inflammatory skin treatment with Boswellia serrata extract.

Molecularly imprinted bacterial cellulose for sustained-release delivery of quercetin

Bacterial cellulose (BC) has been used in the combination with molecularly imprinted polymer (MIP) for controlled-release drug delivery. In the present study, the molecular imprinting was directly performed on BC to avoid the use of synthetic materials for sustained-release of quercetin, which was used as the template molecule. The phase inversion method was successfully used to prepare molecularly imprinted BC (MI-BC). The molecular recognition ability and controlled drug release behavior of MI-BC were then evaluated. MI-BC was found to have approximately 1.6 times higher ability to bind quercetin than the non-imprinted BC (NI-BC) did. The composite membrane containing MI-BC and quercetin (MI-BC-com) delayed and sustained drug release more effectively than the composite membrane containing NI-BC and quercetin (NI-BC-com). MI-BC-com released quercetin approximately two times more slowly than NI-BC-com did at the final hour of the drug release study. The mechanism of quercetin release followed the Higuchi model. Due to the relatively simple method of preparing the drug delivery system without using synthetic MIP, the application of MI-BC may be of great interest in medicine and pharmaceutics.

Bacterial Cellulose as a Versatile Platform for Research and Development of Biomedical Materials

The unique pool of features found in intracellular and extracellular bacterial biopolymers attracts a lot of research, with bacterial cellulose (BC) being one of the most versatile and common. BC is an exopolysaccharide consisting solely of cellulose, and the variation in the production process can vary its shape or even its composition when compounding is applied in situ. Together with ex situ modification pathways, including specialised polymers, particles or exclusively functional groups, BC provides a robust platform that yields complex multifunctional compounds that go far beyond ultra-high purity, intrinsic hydrophilicity, mechanical strength and biocompatibility to introduce bioactive, (pH, thermal, electro) responsive, conductive and ‘smart’ properties. This review summarises the research outcomes in BC-medical applications, focusing mainly on data from the past decade (i.e., 2010–2020), with special emphasis on BC nanocomposites as materials and devices applicable in medicine. The high purity and unique structural/mechanical features, in addition to its capacity to closely adhere to irregular skin surfaces, skin tolerance, and demonstrated efficacy in wound healing, all stand as valuable attributes advantageous in topical drug delivery. Numerous studies prove BC compatibility with various human cells, with modifications even improving cell affinity and viability. Even BC represents a physical barrier that can reduce the penetration of bacteria into the tissue, but in its native form does not exhibit antimicrobial properties, therefore carious modifications have been made or specific compounds added to confer antimicrobial or anti-inflammatory properties. Progress in the use of BC-compounds as wound dressings, vascular grafts, and scaffolds for the treatment of cartilage, bone and osteochondral defects, the role as a basement membrane in blood-brain barrier models and many more are discussed to particular extent, emphasising the need for BC compounding to meet specific requirements.

The Nanofication and Functionalization of Bacterial Cellulose and Its Applications

Since economic and environmental issues have become critical in the last several years, the amount of sustainable bio-based production has increased. In this article, microbial polysaccharides, including bacterial cellulose (BC), are analyzed as promising resources with the potential for applications in biofields and non-biofields. Many scientists have established various methods of BC production, nanofication, and functionalization. In particular, this review will address the essential advances in recent years focusing on nanofication methods and nanoficated BC applications as well as functionalization methods and functionalized BC applications.

Functionalized Bacterial Cellulose Microparticles for Drug Delivery in Biomedical Applications

Background:

Bacterial cellulose (BC) has recently attained greater interest in various research fields, including drug delivery for biomedical applications. BC has been studied in the field of drug delivery, such as tablet coating, controlled release systems and prodrug design.

Objective:

In the current work, we tested the feasibility of BC as a drug carrier in microparticulate form for potential pharmaceutical and biomedical applications.

Method :

For this purpose, drug-loaded BC microparticles were prepared by simple grinding and injection moulding method through regeneration. Model drugs, i.e., cloxacillin (CLX) and cefuroxime (CEF) sodium salts were loaded in these microparticles to assess their drug loading and release properties. The prepared microparticles were evaluated in terms of particle shapes, drug loading efficiency, physical state of the loaded drug, drug release behaviour and antibacterial properties.

Results:

The BC microparticles were converted to partially amorphous state after regeneration. Moreover, the loaded drug was transformed into the amorphous state. The results of scanning electron microscopy (SEM) showed that microparticles had almost spherical shape with a size of ca. 350-400 μm. The microparticles treated with higher drug concentration (3%) exhibited higher drug loading. Keeping drug concertation constant, i.e., 1%, the regenerated BC (RBC) microparticles showed higher drug loading (i.e., 37.57±0.22% for CEF and 33.36±3.03% for CLX) as compared to as-synthesized BC (ABC) microparticles (i.e., 9.46±1.30% for CEF and 9.84±1.26% for CLX). All formulations showed immediate drug release, wherein more than 85% drug was released in the initial 30 min. Moreover, such microparticles exhibited good antibacterial activity with larger zones of inhibition for drug loaded RBC microparticles as compared to corresponding ABC microparticles.

Conclusion :

Drug loaded BC microparticles with immediate release behaviour and antibacterial activity were fabricated. Such functionalized microparticles may find potential biomedical and pharmaceutical applications.