With the increasing number of surgical bone grafts per year, the application of biomaterials in tissue engineering has become a popular issue. In the present work, the potential of biocellulose-nanofibre-reinforced polyurethane nanocomposites to act as bone scaffold implants is established. Investigating properties of polyurethane shows that this widely applied biomaterial group cannot fulfil all properties required for bone implants in a stand-alone fashion. Bone implants require a high Young's modulus and tensile strength but low strain which makes it difficult to find a suitable polyurethane since higher hard segment content will reduce tensile strength and lower hard segment content will reduce the Young's modulus. Other factors such as biodegradation also become important. A literature review on carbon nanotube and nanofibre composites with polyurethanes shows that nanofibrous reinforcement leads to favourable implant properties. Young's modulus and tensile strength increase dramatically. Other properties such as thermal conductivity and viscosity are also affected. These types of nanofibrous materials, however, are the subject of an ongoing debate about toxicity and their use in bone implants is questionable. Biocellulose nanofibres formed from bacteria (also called bacterial cellulose (BC)) possess favourable mechanical properties and are highly biocompatible. A survey on works done on BC nanofibres and their composites show that nanostructured biocomposites that contains the nanofibres reinforced in polymer composites result in changes that are comparable to those of carbon nanotubes in regards to bone scaffold applications. Showing improvement on biocompatibility and mechanical properties, biocellulose nanofibre reinforcement on polyurethanes possesses strong potential for bone implants and other tissue-engineering applications.

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Anorectal abscesses are commonly encountered in clinical surgical practice. These abscesses require surgical management. Supralevator abscesses are thought to originate either from an ischiorectal or intersphincteric abscess extension or from an intraperitoneal source. These abscesses are quite uncommon and present a difficult surgical problem. We present a case here of a 42-year-old female with a recurrent supralevator abscess requiring multiple surgical procedures for adequate drainage and care of her abscess.

Encapsulation in self-assembled block copolymer (BCP) based nanoparticles (NPs) is a common approach to enhance hydrophobic drug solubility, and nanoprecipitation processes in particular can yield high encapsulation efficiency (EE). However, guiding principles for optimizing polymer, drug, and solvent selection are critically needed to facilitate rapid design of drug nanocarriers. Here, we evaluated the relationship between drug-polymer compatibility and concentration ratios on EE and nanocarrier size. Our studies employed a panel of four drugs with differing molecular structures (i.e., coumarin 6, dexamethasone, vorinostat/SAHA, and lutein) and two BCPs [poly(caprolactone)-b-poly(ethylene oxide) (PCL-b-PEO) and poly(styrene)-b-poly(ethylene oxide) (PS-b-PEO)] synthesized using three nanoprecipitation processes [i.e., batch sonication, continuous flow flash nanoprecipitation (FNP), and electrohydrodynamic mixing-mediated nanoprecipitation (EM-NP)]. Continuous FNP and EM-NP processes demonstrated up to 50% higher EE than batch sonication methods, particularly for aliphatic compounds. Drug-polymer compatibilities were assessed using Hansen solubility parameters, Hansen interaction spheres, and Flory Huggins interaction parameters, but few correlations were EE observed. Although some Hansen solubility (i.e., hydrogen bonding and total) and Flory Huggins interaction parameters were predictive of drug-polymer preferences, no parameter was predictive of EE trends among drugs. Next, the relationship between polymer: drug molar ratio and EE was assessed using coumarin 6 as a model drug. As polymer:drug ratio increased from <1 to 3–6, EE approached a maximum (i.e., ∼51% for PCL BCPs vs. ∼44% PS BCPs) with Langmuir adsorption behavior. Langmuir behavior likely reflects a formation mechanism in which drug aggregate growth is controlled by BCP adsorption. These data suggest polymer:drug ratio is a better predictor of EE than solubility parameters and should serve as a first point of optimization.

Sustainable food production is a grand challenge facing the global economy. Traditional agricultural practice requires numerous interventions, such as application of nutrients and pesticides, of which only a fraction are utilized by the target crop plants. Controlled release systems (CRSs) designed for agriculture could improve targeting of agrochemicals, reducing costs and improving environmental sustainability. CRSs have been extensively used in biomedical applications to generate spatiotemporal release patterns of targeted compounds. Such systems protect encapsulant molecules from the external environment and off-target uptake, increasing their biodistribution and pharmacokinetic profiles. Advanced ‘smart’ release designs enable on-demand release in response to environmental cues, and theranostic systems combine sensing and release for real-time monitoring of therapeutic interventions. This review examines the history of biomedical CRSs, highlighting opportunities to translate biomedical designs to agricultural applications. Common encapsulants and targets of agricultural CRSs are discussed, as well as additional demands of these systems, such as need for high volume, low cost, environmentally friendly materials and manufacturing processes. Existing agricultural CRSs are reviewed, and opportunities in emerging systems, such as nanoparticle, ‘smart’ release, and theranostic formulations are highlighted. This review is designed to provide a guide to researchers in the biomedical controlled release field for translating their knowledge to agricultural applications, and to provide a brief introduction of biomedical CRSs to experts in soil ecology, microbiology, horticulture, and crop sciences.

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