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.

Acanthamoeba keratitis (AK) is most commonly found in contact lens wearers with poor lens care hygiene. Recent reports have indicated an increase in cases of AK in the United States associated with the use of Complete MoisturePlus multipurpose solution. This association may not appear explainable by differences in Acanthamoeba kill rates among multipurpose solutions. In this study the physiologic response of Acanthamoeba trophozoites to incubation in various contact lens solutions was investigated. Acanthamoeba trophozoites were incubated in commercial and experimental solutions and the percentage encystment and viability determined in conjunction with microscopic analysis of cyst formation. Among commercial products, MoisturePlus solution induced encystment within 6 to 24 hr of incubation. Only immature cysts formed which failed to mature even after 5 days incubation in the solution although they remained viable. Experimental formulations of MoisturePlus solution, modified by omitting key ingredients, identified propylene glycol as the agent responsible for inducing encystment. However, tests of other commercial solutions containing propylene glycol produced reduced or no encystment. The presence of propylene glycol was shown to be the key factor in inducing Acanthamoeba encystment. However, the reduced or absence of encystment in other commercial solutions containing propylene glycol suggests additional factors, such the buffering system, may be involved in the phenomenon. How these observations relate to the solution's role in the reported association with AK is unclear. Nevertheless, it is recommended that all lens care products be tested for propensity to induce Acanthamoeba encystment and formulations containing propylene glycol may warrant special scrutiny.

In the human innate immune system, stimulated phagocytes release reactive nitrogen intermediates that can react with superoxide to form the powerful oxidant peroxynitrite and other less abundant species. In this study, the efficacy of hydrogen peroxide (H₂O₂) and acidified nitrite (NaNO₂) alone and in combination was compared against a variety of bacteria, fungi and protozoa. Challenge test assays based on the international standard (ISO 14729) were used to determine the antimicrobial activity of H₂O₂ and acidified NaNO₂ at pH 5 alone and in combination against Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Mycobacterium aurum, Bacillus subtilis spores, Candida albicans, Fusarium solani conidia and Acanthamoeba polyphaga trophozoites and cysts. When tested alone, both H₂O₂ (0.4% v/v) and NaNO₂ (2 mg/mL, pH 5) produced a ≥4 log reduction in viability after 4 h of exposure for all bacteria and A. polyphaga trophozoites, but not B. subtilis spores, F. solani and A. polyphaga cysts, which gave a ≤1 log kill after 6 h, and M. aurum, which gave a <1 log kill with NaNO₂ only. However, the combination of H₂O₂ and NaNO₂ resulted in a ≥4 log kill of all test organisms within 1 h. Addition of NaNO₂ also enhanced the antimicrobial efficacy of a H₂O₂-based contact lens disinfection system. The findings of this study demonstrate that acidified NaNO₂ can significantly enhance the antimicrobial activity of H₂O₂ probably through the generation of peroxynitrite. The addition of acidified nitrite to 3% (v/v) H₂O₂ solution may represent an improved one-step method for the disinfection of contact lenses, especially against highly resistant cysts of Acanthamoeba spp.

Purpose: To compare the antimicrobial effect of topical anesthetics, antivirals, antibiotics, and biocides on the viability of Acanthamoeba cysts and trophozoites in vitro. Methods: Amoebicidal and cysticidal assays were performed against both trophozoites and cysts of Acanthamoeba castellanii (ATCC 50370) and Acanthamoeba polyphaga (ATCC 30461). Test agents included topical ophthalmic preparations of common anesthetics, antivirals, antibiotics, and biocides. Organisms were exposed to serial two-fold dilutions of the test compounds in the wells of a microtiter plate to examine the effect on Acanthamoeba spp. In addition, the toxicity of each of the test compounds was determined against a mammalian cell line. Results: Proxymetacaine, oxybuprocaine, and especially tetracaine were all toxic to the trophozoites and cysts of Acanthamoeba spp., but lidocaine was well tolerated. The presence of the benzalkonium chloride (BAC) preservative in levofloxacin caused a high level of toxicity to trophozoites and cysts. With the diamidines, the presence of BAC in the propamidine drops was responsible for the activity against Acanthamoeba spp. Hexamidine drops without BAC showed good activity against trophozoites, and the biguanides polyhexamethylene biguanide, chlorhexidine, alexidine, and octenidine all showed excellent activity against trophozoites and cysts of both species. Conclusions: The antiamoebic effects of BAC, povidone iodine, and tetracaine are superior to the current diamidines and slightly inferior to the biguanides used in the treatment for Acanthamoeba keratitis. Translational Relevance: Ophthalmologists should be aware that certain topical anesthetics and ophthalmic preparations containing BAC prior to specimen sampling may affect the viability of Acanthamoeba spp. in vivo, resulting in false-negative results in diagnostic tests.