Smart polymer Dotaz Zobrazit nápovědu
Lékové formy s elektronickým prvkem je možné zařadit mezi jedny z nejmodernějších a nejinovativnějších lékových systémů posledních několika dekád. Inkorporace elektronického/digitálního prvku nabízí řadu výhod, jako např. možnost přesného načasování uvolnění léčivé látky v požadované lokaci gastrointestinálního traktu, sběr biometrických dat, či nezpochybnitelný průkaz adherence pacienta k terapii. V současné době je možné pozorovat vývoj oboru do dvou hlavních směrů. Tím prvním je využití těchto systémů ve spojení s řízeným uvolňováním při absorpčních a obecně farmakokinetických studiích nových látek. Druhým směrem je pak digitální monitoring adherence k léčbě. Tento stručný přehled pojednává krátce o historii problematiky, přináší informace o obou zmíněných odvětvích a zmiňuje zásadní zástupce obou skupin a jejich využití.
Delivery systems with an electronic element can be classified as one of the last few decades' most modern and innovative pharmaceutical systems. Incorporating an electronic/digital element offers several advantages, such as the possibility of the precise timing of the drug released in the desired location of the gastrointestinal tract, collection of biometric data, or indisputable proof of the patient's adherence to therapy. Currently, it is possible to observe the development of the field in two main directions. The first one is using these systems in conjunction with the controlled release principle in absorption and general pharmacokinetic studies of new substances. The second direction is digital monitoring of therapy adherence. This brief overview briefly mentions the field's history, brings information about the two main branches, and states the essential systems of both branches and their use.
Tento návrh jednoduché metody vizualizace daktyloskopických stop na základě elektrochemické depozice polyfenazinových barviv (polyneutrální červeně a polytoluidinové modři) z neutrálního prostředí, kdy je minimalizováno poškození genetické informace, by mohl usnadnit snímání otisků prstů z nábojnic ve forenzní praxi. Parametry elektrochemických metod cyklické voltametrie a chronoamperometrie (základní elektrolyt, aplikovaný potenciál, doba depozice nebo potenciálový rozsah a počet cyklů) byly postupně optimalizovány, dokud nebyl otisk dostatečně viditelný. Morfologie a struktura modifikovaných povrchů daktyloskopických stop a polyfenazinových filmů byly studovány pomocí skenovací elektronové mikroskopie. Je předpokládán další rozvoj metody a především aplikace metody na vystřelené nábojnice.
A simple fingerprint visualization method based on the electrochemical deposition of polytoluidine blue (PTB) and polyneutral red (PNR) from a neutral environment with the possibility of minimal damage to the genetic information could facilitate fingerprinting from cartridge cases in forensic practice. The parameters of both visualization methods (supporting electrolyte, applied potential, deposition time or potential range, and number of cycles) were optimized until the imprint was sufficiently visible. The morphology and structure of modified fingerprint surfaces and polyphenazine films were studied using scanning electron microscopy. It is assumed that the method will be applied in the future to fired cartridges, which are crucial in forensics.
Treating oral diseases remains challenging as API is quickly washed out of the application site by saliva turnover and mouth movements. In situ gels are a class of application forms that present sol-gel transition's ability as a response to stimuli. Their tunable properties are provided using smart polymers responsible for stimuli sensitivity, often providing mucoadhesivity. In this study, antimicrobial in situ gels of thermosensitive and pH-sensitive polymers loaded with silver nanoparticles were prepared and evaluated. The nanoparticles were prepared by green synthesis using Agrimonia eupatoria L. extract. According to the data analysis, the in situ gel with the most promising profile contained 15 % of Pluronic® F-127, 0.25 % of methylcellulose, and 0.1 % of Noveon® AA-1. Pluronic® F-127 and methylcellulose significantly increased the viscosity of in situ gels at 37 °C and shear rates similar to speaking and swallowing. At 20 °C, a behavior close to a Newtonian fluid was observed while being easily injectable (injection force 13.455 ± 1.973 N). The viscosity of the formulation increased with temperature and reached 2962.77 ± 63.37 mPa·s (37 °C). A temperature increase led to increased adhesiveness and rigidity of the formulation. The critical sol-gel transition temperature at physiological pH was 32.65 ± 0.35 °C. 96.77 ± 3.26 % of Ag NPs were released by erosion and dissolution of the gel after 40 min. The determination of MIC showed effect against E. coli and S. aureus (0.0625 mM and 0.5000 mM, respectively). The relative inhibition zone diameter of the in situ gel was 73.32 ± 11.06 % compared to gentamicin sulfate. This work discusses the optimization of the formulation of novel antibacterial in situ gel for oromucosal delivery, analyses the impact of the concentration of excipients on the dependent variables, and suggests appropriate evaluation of the formulation in terms of its indication. This study offers a promising dosage form for local treatment of oral diseases.
Nano-sized carriers are widely studied as suitable candidates for the advanced delivery of various bioactive molecules such as drugs and diagnostics. Herein, the development of long-circulating stimuli-responsive polymer nanoprobes tailored for the fluorescently-guided surgery of solid tumors is reported. Nanoprobes are designed as long-circulating nanosystems preferably accumulated in solid tumors due to the Enhanced permeability and retention effect, so they act as a tumor microenvironment-sensitive activatable diagnostic. This study designs polymer probes differing in the structure of the spacer between the polymer carrier and Cy7 by employing pH-sensitive spacers, oligopeptide spacers susceptible to cathepsin B-catalyzed enzymatic hydrolysis, and non-degradable control spacer. Increased accumulation of the nanoprobes in the tumor tissue coupled with stimuli-sensitive release behavior and subsequent activation of the fluorescent signal upon dye release facilitated favorable tumor-to-background ratio, a key feature for fluorescence-guided surgery. The probes show excellent diagnostic potential for the surgical removal of intraperitoneal metastasis and orthotopic head and neck tumors with very high efficacy and accuracy. In addition, the combination of macroscopic resection followed by fluorescence-guided surgery using developed probes enable the identification and resection of most of the CAL33 intraperitoneal metastases with total tumor burden reduced to 97.2%.
- MeSH
- chytré polymery * MeSH
- fluorescence MeSH
- fluorescenční barviva chemie MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- nádorové mikroprostředí MeSH
- nádory hlavy a krku * diagnostické zobrazování chirurgie MeSH
- polymery MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This paper introduces a new class of amphiphilic block copolymers created by combining two polymers: polylactic acid (PLA), a biocompatible and biodegradable hydrophobic polyester used for cargo encapsulation, and a hydrophilic polymer composed of oligo ethylene glycol chains (triethylene glycol methyl ether methacrylate, TEGMA), which provides stability and repellent properties with added thermo-responsiveness. The PLA-b-PTEGMA block copolymers were synthesized using ring-opening polymerization (ROP) and reversible addition-fragmentation chain transfer (RAFT) polymerization (ROP-RAFT), resulting in varying ratios between the hydrophobic and hydrophilic blocks. Standard techniques, such as size exclusion chromatography (SEC) and 1H NMR spectroscopy, were used to characterize the block copolymers, while 1H NMR spectroscopy, 2D nuclear Overhauser effect spectroscopy (NOESY), and dynamic light scattering (DLS) were used to analyze the effect of the hydrophobic PLA block on the LCST of the PTEGMA block in aqueous solutions. The results show that the LCST values for the block copolymers decreased with increasing PLA content in the copolymer. The selected block copolymer presented LCST transitions at physiologically relevant temperatures, making it suitable for manufacturing nanoparticles (NPs) and drug encapsulation-release of the chemotherapeutic paclitaxel (PTX) via temperature-triggered drug release mechanism. The drug release profile was found to be temperature-dependent, with PTX release being sustained at all tested conditions, but substantially accelerated at 37 and 40 °C compared to 25 °C. The NPs were stable under simulated physiological conditions. These findings demonstrate that the addition of hydrophobic monomers, such as PLA, can tune the LCST temperatures of thermo-responsive polymers, and that PLA-b-PTEGMA copolymers have great potential for use in drug and gene delivery systems via temperature-triggered drug release mechanisms in biomedicine applications.
- Publikační typ
- časopisecké články MeSH
- Klíčová slova
- nanosondy, označení nádoru, hranice nádoru,
- MeSH
- chytré polymery MeSH
- lidé MeSH
- nádory * chirurgie MeSH
- nanotechnologie metody MeSH
- Check Tag
- lidé MeSH
Smart hydrogels are special type of hydrogels that undergo solution-gelation transition in response to alterations in the environment. Solution-gel transformation is brought about through either physical or chemical cross-linking that occur between the hydrogel chains. Various stimulating factors have been identified to be responsible for the change in the physical state of the intelligent hydrogel. The most important triggering factors are the temperature, pH, ions, electrical signalling, magnetic field, glucose, light and others. Each of these stimulating factors can trigger the swelling of the hydrogel through unique mechanism. Many of these triggering factors are characteristics of the biological systems which make the smart polymers quite beneficial for different biomedical applications. Numerous natural and synthetic polymers have been distinguished to act as smart materials. These polymers impressed the scientists to use them in many biomedical and industrial applications such as drug delivery systems, gene therapy applications, tissue engineering and many other applications.
The main task of the research is to acquire fundamental knowledge about the effect of polymer structure on the physicochemical properties of films. A novel meta-material that can be used in manufacturing sensor layers was developed as a model. At the first stage, poly(sodium 4-styrenesulfonate) (PNaSS) cross-linked microspheres are synthesized (which are based on strong polyelectrolytes containing sulfo groups in each monomer unit), and at the second stage, PNaSS@PEDOT microspheres are formed. The poly(3,4-ethylenedioxythiophene) (PEDOT) shell was obtained by the acid-assisted self-polymerization of the monomer; this process is biologically safe and thus suitable for biomedical applications. The suitability of electrochemical impedance spectroscopy for E. coli detection was tested; it was revealed that the attached bacterial wall was destroyed upon application of constant oxidation potential (higher than 0.5 V), which makes the PNaSS@PEDOT microsphere particles promising materials for the development of antifouling coatings. Furthermore, under open-circuit conditions, the walls of E. coli bacteria were not destroyed, which opens up the possibility of employing such meta-materials as sensor films. Scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle, and wide-angle X-ray diffraction methods were applied in order to characterize the PNaSS@PEDOT films.
- MeSH
- bicyklické sloučeniny heterocyklické chemie MeSH
- Escherichia coli * MeSH
- mikrosféry MeSH
- polymery * chemie MeSH
- Publikační typ
- časopisecké články MeSH
Polymers with lower critical solution temperature (LCST) are molecularly soluble in their solutions at low temperatures but, when heated above their cloud point temperature, these polymers assemble into supramolecular particles or macroscopic precipitates. These particles or precipitated polymeric depots can be used for diagnostics, targeted drug delivery, controlled drug release from a depot or a combination of diagnostics and therapy (theranostics). Herein, we describe smart polymer systems which contain N-(2,2-difluoroethyl)acrylamide monomer unit (DFEA) and form polymeric nanoparticles upon heating or precipitate after injection to polymeric implants/depots. Due to a high fluorine content and to relaxation properties of this element, these polymers are suitable as tracers for the 19F MRI method, a promising non-invasive diagnostic tool. Moreover, DFEA copolymers can contain monomers that react to additional physicochemical properties, resulting in multiresponsive polymers (pH- or redox-responsive), which can be used for smart drug delivery systems with controlled release of drugs in the target environment.
- MeSH
- dichlorethyleny MeSH
- kontrastní látky * MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- Check Tag
- lidé MeSH
Recently, the stimuli-responsive polymers get increased scientific interest due to the ability to reversibly alter their physicochemical properties. They are often referred to as smart, environmental-sensitive or intelligent polymers. This review provides fundamental information on various types of smart polymers responsive to biological, physical and chemical stimuli with examples of their use in the preparation of smart hydrogels and in situ gels with controlled or targeted drug release.
