Design of Biopolymer-Based Interstitial Therapies for the Treatment of Glioblastoma

Glioblastoma multiforme (GBM) is the most common form of primary brain cancer and has the highest morbidity rate and current treatments result in a bleak 5-year survival rate of 5.6%. Interstitial therapy is one option to increase survival. Drug delivery by interstitial therapy most commonly makes use of a polymer implant encapsulating a drug which releases as the polymer degrades. Interstitial therapy has been extensively studied as a treatment option for GBM as it provides several advantages over systemic administration of chemotherapeutics. Primarily, it can be applied behind the blood–brain barrier, increasing the number of possible chemotherapeutic candidates that can be used and reducing systemic levels of the therapy while concentrating it near the cancer source. With interstitial therapy, multiple drugs can be released locally into the brain at the site of resection as the polymer of the implant degrades, and the release profile of these drugs can be tailored to optimize combination therapy or maintain synergistic ratios. This can bypass the blood–brain barrier, alleviate systemic toxicity, and resolve drug resistance in the tumor. However, tailoring drug release requires appropriate consideration of the complex relationship between the drug, polymer, and formulation method. Drug physicochemical properties can result in intermolecular bonding with the polymeric matrix and affect drug distribution in the implant depending on the formulation method used. This review is focused on current works that have applied interstitial therapy towards GBM, discusses polymer and formulation methods, and provides design considerations for future implantable biodegradable materials.

A hybrid treatment modality of a subtrochanteric femoral fracture in a patient with osteoporosis due to a renal Fanconi syndrome: a case report

A 24-year-old male with an idiopathic renal Fanconi syndrome presented to our ER after a low-energetic fall. Conventional imaging revealed a right subtrochanteric femoral fracture, severely decreased bone quality and cannulated collum femoris screws on the contralateral side. Regular plate-screw osteosynthesis or cephalomedullary implantation was deemed insufficient, due to a high iatrogenic and periprosthetic fracture probability. The decision was made to perform a plate-screw osteosynthesis combined with an intramedullary polymer bone enhancement (IlluminOss), to minimize this risk. No complications occurred perioperatively. The patient was able to walk independently two months postoperatively. This case shows that use of polymer implant as an enhancement of osteosynthesis in repair of fractures in the Fanconi syndrome is a safe and possible useful treatment method.

SIMULATION OF WOUND PROCESS IN EXPERIMENTAL SURGERY

Aim. To study morphological changes in aseptic and purulent soft-tissue wounds using the developed models in animal experiments.Materials and methods. The study was conducted on 70 white non-linear laboratory male rats aged 5 months and weighing 300–350 g. All the investigations were performed in accordance with ethical norms and documents regulating animal experiments. An experimental wound was simulated with the introduction of an implant into soft tissues using a layer-by-layer incision to the required depth. A sterile hydrophilic polymer implant was used for simulating an aseptic wound. A purulent wound was simulated using a porous polymer implant initially saturated with a suspension of a bacterial pathogen at a concentration of 10 5–10 12 microbial cells per 1 ml of suspension. The wounds were sutured layer by layer to form corresponding models. The implants was removed surgically on the 7th day. Statistical analysis of the study results was carried out by Windows 10 operating system using STATISTICA 6.1 (StatSoft Inc., USA) and Excel (Microsoft Offi ce 2010). The hypothesis of normal cumulative distribution in the samples was verifi ed via the Shapiro — Wilk and Kolmogorov — Smirnov tests. The signifi cance level threshold was set to p<0.05. Differences between quantitative parameters with a normal distribution were evaluated using the Student’s t-test, whereas independent samples were assessed via the non-parametric Mann — Whitney test. In all cases, differences were considered statistically signifi cant at p<0.05. The signifi cance level of the relationship between the two qualitative variables was verifi ed using the Pearson’s chi squared test (χ2 ). The study was approved at a meeting of the Independent Ethics Committee of the Kuban State Medical University (Minutes No. 63 of 21 May 2018).Results. The analysis of the obtained results has allowed optimal models for the formation of aseptic and purulent soft-tissue wounds in animal experiments to be selected.Conclusion. The proposed method of modeling aseptic and purulent wounds in animal experiments can be used in clinical and morphological studies of the wound process, as well as in assessing the effectiveness of various wound treatment methods.

Model of Controlled Drug Release from the Polymer Implant

A mathematical model for analysis of features of the drug release , previously introduced into a polymer implant, into a biological tissue is proposed. A carbon nanolayer obtained as a result of plasma-immersion ion implantation was created to improve biocompatibility with biological tissue on the surface of the implant. The medicine can go through micro-ruptures in this layer. Calculations show that the carbon layer allows a uniform release of the drug.

Manufacturing of metal-polymer composites for medical applications

Purpose: The purpose of the article is to present the design and fabrication methodology of metallic scaffolds, with the shape and dimensions defined by the designer, coated with a thin layer of polymer. Design/methodology/approach: The methodology proposed covers Computer Aided Materials Design (CAMD), fabrication of metallic scaffolds using a machine for Selective Laser Melting (SLM), the deposition of a thin layer of polymers onto scaffolds using coldwork and hot-work polymerisers, as well as mechanical finishing. The strength of the newly developed metal-polymer composites to three-point bending was examined and their fractures were viewed with SEM. Findings: A fabrication method of implants in the form of scaffolds coated with a thin layer of polymer with the dimensions and shape closely matching the losses in a patient’s hard and/or soft palate. Practical implications: After clinical tests, a metal-polymer implant may be a very beneficial alternative for patients with palate losses using traditional prostheses until now. Originality/value: The individualised implants of palate pieces in the form of scaffolds coated with a thin layer of polymer, submitted for patent protection, do not have their counterparts, which is representing their originality.