Membrane creates the functions of protection, supporting, dispersion and separation. More functions can be designed by modifying membrane surface and grafting/loading selective ligands or catalysts on the membrane, thus membrane technology has been widely applied in biological detection, and its application approaches becomes diverse. Rational design of functional membranes can meet the demands in different steps of biological detection process, including sample pretreatment, preparation, response and sensing. This review summarized the functionalization methods of filtration membranes, applications of membrane technology in sample preparation and detection process, as well as the research on the integration of functional membranes. By revisiting the research progress on functional membrane design, preparation and applications for biological detection, it is expected to take better advantage of membrane materials structure and performance for constructing efficient and stable detection platform, which is more "adapted" to the detection environment.
Membranes, Artificial

OBJECTIVETo use a new kind of fixing material, i.e. Sol-Gel organic-inorganic hybridized material to immobilize bacterium to detect Biochemical oxygen demand quickly.

METHODSThe biosensor was fabricated using a thin film in which Hansenula anomala was immobilized by sol-gel and an oxygen electrode. The optimum measurement for biochemical oxygen demand was at pH 7.0; 28 degrees C; response time 3 - 12 min. Pure organic compound, sewage and rate of recovery were detected with the biosensor.

RESULTSIt shows that the BOD biosensor can be used to detect many organic compounds such as amino acid, glucide. It is suitable to monitor sewage and industrial waste water which has low level alcohols and phenols. The microbial membrane can work 3 months and remain its 70% activity. It is measured that the rate of recovery of BOD is between 90% to 105% in sewage.

CONCLUSIONThe study confirmed the effectiveness and usefulness of BOD sensor, which is quick, convenient, low cost and reliable with little interference.

Bacteria ; Biosensing Techniques ; instrumentation ; Cells, Immobilized ; Gels ; Membranes, Artificial ; Nylons ; Oxygen ; analysis ; Sewage ; analysis ; microbiology

Chromatography, Micellar Electrokinetic Capillary ; methods ; Liposomes ; Membranes, Artificial ; Pharmaceutical Preparations ; chemistry

BACKGROUNDS/AIMS: Stem cell therapies for liver disease are being studied by many researchers worldwide, but scientific evidence to demonstrate the endocrinologic effects of implanted cells is insufficient, and it is unknown whether implanted cells can function as liver cells. Achieving angiogenesis, arguably the most important characteristic of the liver, is known to be quite difficult, and no practical attempts have been made to achieve this outcome. We carried out this study to observe the possibility of angiogenesis of implanted bio-artificial liver using scaffolds. METHODS: This study used adipose tissue-derived stem cells that were collected from adult patients with liver diseases with conditions similar to the liver parenchyma. Specifically, microfilaments were used to create an artificial membrane and maintain the structure of an artificial organ. After scratching the stomach surface of severe combined immunocompromised (SCID) mice (n=4), artificial scaffolds with adipose tissue-derived stem cells and type I collagen were implanted. Expression levels of angiogenesis markers including vascular endothelial growth factor (VEGF), CD34, and CD105 were immunohistochemically assessed after 30 days. RESULTS: Grossly, the artificial scaffolds showed adhesion to the stomach and surrounding organs; however, there was no evidence of angiogenesis within the scaffolds; and VEGF, CD34, and CD105 expressions were not detected after 30 days. CONCLUSIONS: Although implantation of cells into artificial scaffolds did not facilitate angiogenesis, the artificial scaffolds made with type I collagen helped maintain implanted cells, and surrounding tissue reactions were rare. Our findings indicate that type I collagen artificial scaffolds can be considered as a possible implantable biomaterial.
Actin Cytoskeleton ; Adult ; Animals ; Artificial Organs ; Biocompatible Materials ; Collagen Type I* ; Humans ; Liver Diseases ; Liver* ; Membranes, Artificial ; Mice ; Stem Cells* ; Stomach ; Tissue Scaffolds ; Vascular Endothelial Growth Factor A

OBJECTIVETo found new interface of human hepatocyte/poly propylene with good cytocompatibility for made polypropylene hollow fibers bioreactor of bioartificial liver in future.

METHODSUsing the macromolecular hydroperoxide groups on the polypropylene membrane surface as initiators, acrylamides were polymerized on the polypropylene membranes, under induction by both UV irradiation and Fe2+ reduction. Growth characteristics of human hepatocyte L-02 were detected when it was cultured on polystyrene, polypropylene and modified polypropylene membrane surface.

RESULTSWater contact angle measurement of the polypropylene and the modified polypropylene membranes decreased from (72 +/- 5) degrees to (30 +/- 4) degrees , which indicated that the hydrophilicity of the membrane was improved obviously after the grafting modification. Human hepatocyte L-02 could not adhere and spread on modified polypropylene membrane surface, and grown in spheroidal aggregate with higher density and higher proliferation ratio measured by MTT method.

CONCLUSIONSAcrylamide polymerized on the polypropylene membranes is a good method which not only improved human hepatocytes cytocompatibility but also found a new simple culture method with spheroidal aggregate culture of human hepatocyte.

Cell Culture Techniques ; methods ; Cell Division ; Cells, Cultured ; Hepatocytes ; cytology ; Humans ; Liver, Artificial ; Membranes, Artificial ; Polypropylenes ; chemistry ; Surface Properties ; Tissue Engineering ; methods

Membrane separation technology is a major branch in modern separation technology, which is widely applied in chemical, pharmaceutical and other industries. The purpose of this paper is to introduce principle and the application example of the membrane separation technology in medical devices, to analyse the problems existing in the current application, and to discuss the future development direction.
Equipment and Supplies ; Membranes, Artificial ; Technology

Compound membranes of chitosan/hydroxyapatite were prepared by blending. The physical performance showed that the air-water contact angles decreased from chitosan's 103 degrees to chitosan/hydroxyapatite's 57 and the water adsorption rate increased slightly. When immersed into culture medium, the materials adsorbed Ca2+, and low crystalline hydroxyapatite deposited on the surface of the membranes. Chitosan/hydroxyapatite compound membranes could enhance the attachment and proliferation of mescenchymal stem cells (MSCs). After 12 days' induction on the materials, the alkaline phosphatase (ALP) activity value of MSCs on the compound membrane was 10.1, being much higher than 1.6 on chitosan membrane (P<0.01). All these results indicate that chitosan does not have very good affinity for MSCs, but the biocompatibility of chitosan can be apparently enhanced after mixing with hydroxyapatite. The compound membrane stimulates MSCs to differentiate into osteoblasts and it may be a good potential material for bone substitution.
Alkaline Phosphatase ; metabolism ; Animals ; Bone Substitutes ; pharmacology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Chitosan ; chemical synthesis ; pharmacology ; Durapatite ; chemical synthesis ; pharmacology ; Membranes, Artificial ; Mesenchymal Stromal Cells ; cytology ; Rats

In this study, porous polymer (PLA/PCL) membrane was first treated with ethanol to become hydrophilic, and then immersed into DMEM with 50% fetal bovine serum to enhance the affinity to cells. MSCs cultured in osteogenic medium were loaded into the membrane at density of 5 x 10(6)/cm2 for 7 days, and scanning electrical microscope was used to observe the growth of the MSCs. The growth of MSCs inside the constructs was functionally well, and the cells proliferated with the time of culture. We concluded from current study that the membrane had satisfactory biocompatibility and the constructs could be used to guided bone regeneration.
Animals ; Biocompatible Materials ; Bone Marrow Cells ; cytology ; Bone Regeneration ; Bone Substitutes ; Cell Differentiation ; Cell Division ; Cells, Cultured ; Extracellular Matrix ; Female ; Guided Tissue Regeneration ; Lactic Acid ; Membranes ; Membranes, Artificial ; Mesenchymal Stromal Cells ; cytology ; Polyesters ; Polymers ; Tissue Engineering

Purinergic receptors play an important role in regulating gastrointestinal (GI) motility. Interstitial cells of Cajal (ICCs) are pacemaker cells that regulate GI smooth muscle activity. We studied the functional roles of external adenosine 5′-triphosphate (ATP) on pacemaker activity in cultured ICCs from mouse small intestines by using the whole-cell patch clamp technique and intracellular Ca²⁺ ([Ca²⁺]ᵢ) imaging. External ATP dose-dependently depolarized the resting membrane and produced tonic inward pacemaker currents, and these effects were antagonized by suramin, a purinergic P2 receptor antagonist. ATP-induced effects on pacemaker currents were suppressed by an external Na⁺-free solution and inhibited by the nonselective cation channel blockers, flufenamic acid and niflumic acid. The removal of external Ca²⁺ or treatment with thapsigargin (inhibitor of Ca²⁺ uptake into endoplasmic reticulum) inhibited the ATP-induced effects on pacemaker currents. Spontaneous [Ca²⁺]ᵢ oscillations were enhanced by external ATP. These results suggest that external ATP modulates pacemaker activity by activating nonselective cation channels via external Ca²⁺ influx and [Ca²⁺]ᵢ release from the endoplasmic reticulum. Thus, it seems that activating the purinergic P2 receptor may modulate GI motility by acting on ICCs in the small intestine.
Adenosine ; Adenosine Triphosphate ; Animals ; Endoplasmic Reticulum ; Flufenamic Acid ; Interstitial Cells of Cajal ; Intestine, Small ; Membranes ; Mice ; Muscle, Smooth ; Niflumic Acid ; Pacemaker, Artificial ; Receptors, Purinergic ; Receptors, Purinergic P2 ; Suramin ; Thapsigargin

OBJECTIVE: To investigate and compare the growth of human fetal retinal pigment epithelial (RPE) cells seeded onto electrospun polyamide nanofibers (EPN) or etched pore polyester (EPP), and, further, to explore their possible use as prosthetic Bruch's membrane. METHODS: Human fetal RPE cells were planted onto the EPN, EPP and plastic (control) substrates in Transwells. The cultures were assessed with respect to cell attachment at 2, 4, 8 hours and proliferation at 1, 4, 8 days after seeding. Growth and morphology of the cells were monitored under the phase contrast microscope, and the phenotype was identified by immunofluorescence staining with antibodies against tight junction protein ZO-1. Strips of single EPP coated with nothing or EPP coated with EPN was differently implanted into the subretinal space of two P21 RCS rats for two weeks and the histologic slides of the retina were assessed. RESULTS: Cultured human fetal RPE cells were attached to either EPN or EPP substrates (with seeding on plastic substrate as control). After 8 h, the numbers of adherent cells in the EPN, EPP and control groups were 1.23*10(5)/cm(2), 1.70*10(5)/cm(2), and 1.64*10(5)/cm(2), respectively. The number of RPE cells attached to EPN was obviously less than that to both EPP and control (P<0.05). On the first day, the proliferation of cells on EPN was less than that of EPP and control (P<0.05); but by the 8th day in culture, the proliferation of cells on EPN had increased and was higher than proliferation on both EPP and control (P<0.05). All of the RPE cells cultured on EPN and EPP substrates were in monolayer, and the EPN-attached cells resembled the inner collagenous layer of Bruch's membrane. Immunofluorescence staining showed that the RPE cells cultured on EPN and EPP substrates adopted a higher expression of ZO-1 than that on the plastic control substrate. Subretinal implantation of either EPP alone or EPP as a carrier for free EPN for 2 weeks in P21RCS rats resulted in an expected encapsulation and loss of photoreceptor layer. No toxicity or other adverse reaction was observed in the vicinity of the transplant. CONCLUSION EPN and EPP could maintain human fetal RPE cell attachment and proliferation. Both EPN and EPP appeared to be grossly tolerance and biocompatible with subretinal implantation. EPN represents an intriguing prospect for prosthetic Bruch's membrane replacement because of its similarity in structure to native Bruch's membrane.
Animals ; Biocompatible Materials ; chemistry ; Bruch Membrane ; Cell Proliferation ; Cells, Cultured ; Fetus ; Humans ; Membranes, Artificial ; Nanofibers ; chemistry ; Polyesters ; chemistry ; Porosity ; Rats ; Retinal Pigment Epithelium ; cytology ; growth & development ; Tissue Engineering