Cross-linking albumin

Polymer nanoparticles including nanospheres and nanocapsules (Fig. 1) can be prepared according to numerous methods that have been developed over the last 30 years. The development of these methods occurred in several steps. Historically, the first nanoparticles proposed as carriers for therapeutic applications were made of gelatin and cross-linked albumin. Then, to avoid the use of proteins that may stimulate the immune system and to limit the toxicity of the cross-linking agents, nanoparticles made from synthetic polymers were developed. At first, the nanoparticles were made by emulsion polymerization of acrylamide and by dispersion polymerization of methylmethacry-late.f These nanoparticles were proposed as adjuvants for vaccines. However, since they were made of non-biodegradable polymers, these nanoparticles were rapidly substituted by particles made of biodegradable... 

Thomasset B, Thomasset T, Vejux A et al. Immobilized thylakoids in a cross-linked albumin matrix. Plant Physiol 1982 70 714-722. 

Thylakoids membranes immobilized in a cross-linked albumin-glutaraldehyde matrix have been used to detect PbCl2 and CdCl2 in solution. The photosynthetic activity was measured with an electrochemical micro-cell. The principle of measurement is based on the fact that ambient oxygen. 

Entrapment in resins, and in glutaraldehyde cross-linked albumin gels... 

Serum albumin can be insolubilized by heat or by chemical cross-linking agents, and implantation of glutaraldehyde-cross-linked albumin microbeads containing insulin in diabetic rats has provided elevated blood insulin levels for periods of up to 3 weeks with biodegradation of the remnant implants within 1-2 months (Goosen et a/., 1982, 1983). 

Merhi Y, Roy R, Guidoin R, Hebert J, Mourad W, Slimane SB. Cellular reactions to polyester arterial prostheses impregnated with cross-linked albumin in vivo studies in mice. Biomaterials 1989 10 56-8. 

Furthermore, Chatteijee et ah prepared cross-linked albumin magnetic microspheres and could use them for red blood cell separation. Another work of Chatteijee et al. ° described the incorporation... 

Components/ mechanism of action Light-activated polyethylene-glycol (PEG) polymer sealant for lung tissue. Monomeric (2-octyl cyanoacrylate) formulation tissue adhesive for skin closure. Bovine albumin cross-linked with gluteraldehyde tissue adhesive/sealant. 

Albumin cross-linked with glutaraldehyde is sold at a cost of approximately 90 per ml and comes in a 5 ml kit. The adhesive can be stored at room temperature and preparation time including assembly of the applicator gun can be completed in several minutes. 

The resolution of these columns for protein mixtures, however, was comparably poor. The peak capacity for human serum albumin was near 3 during 20 min gradient elution. Improvement has been reached by covalent binding of PEI (M = 400-600) onto a 330 A silica of 5 pm particle size [38], The peak capacities of ovalbumin and 2a -arid glycoprotein were 30-40 (tgradienl = 20 min). Enhanced peak capacity and resolution probably were due to the more diffuse structure of PEI coupled to silane moieties than that of strictly adsorbed on silica and cross-linked (see Sect, 2.2). Other applications of covalently adsorbed PEI are discussed in Sect. 4.1. 

The cross-linking method relies on bifimctional reagents to form intermolecular linkages between the enzyme molecules to render them insoluble. Often albumin is added as an extender and glutaraldehyde is most commonly employed. This material can then be either formed as a free standing membrane or applied to the inner surface of the dialysis membrane... 

Patwardhan, A.V. and Ataai, M.M., Site accessibility and the pH dependence of the saturation capacity of a highly cross-linked matrix. Immobilized metal affinity chromatography of bovine serum albumin on Chelating Superose, /. Chromatogr. A, 767, 11, 1997. 

Gelatin and albumin nanoparticles have been prepared through desolvation of the dissolved macromolecules by either salts (e.g., sodium sulfate or ammonium sulfate) or ethanol [179-182], This is, in principle, similar to a simple coacervation method. The particles can then be insolubilized through cross-linking with an optimum amount of aldehydes. These phase separation methods avoid the use of oils as the external phase. 

Fig. 10 Release of cromolyn sodium (sodium cromoglycate) from human serum albumin microspheres prepared using a water-oil emulsion technique with 5% glutaraldehyde as cross-linking agent. Dissolution medium pH 7 phosphate buffer. (From Ref. 98.)... 

Figure 15.9 The results of capture ELISA on native RNase A and formalin-treated RNase A. Right panel, native RNase A (curve 1) and unfractionated formalin-treated RNase A (curve 2). Left panel, individual fractions of formalin-treated RNase A monomer (curve 3), dimmer (curve 4), trimer (curve 5), tetramer (curve 6), and a mixture of oligomers with >5 cross-linked proteins (curve 7). The ELISA plate wells were coated with monoclonal antibody against bovine pancreatic RNase A (1 pg/mL) overnight at 4°C and then blocked with bovine serum albumin. The wells were incubated for lh at 37°C in the presence of various concentrations of antigen in lOOpL of PBS. After washing, each plate well received a 1 4000 dilution of horseradish peroxidase conjugated rabbit polyclonal anti-RNase A antibody followed by incubation at ambient temperature for lh. After washing, detection was achieved using a mixture of 2,2,-azino-di-(3-ethylbenzthiazoline-6-sulphonate) and hydrogen peroxide. Absorbance was monitored at 405 nm. See Rait etal.11 for details.

Hopwood, D. (1969) Comparison of the cross-linking abilities of glutaraldehyde, formaldehyde, and a-hydroxyadipaldehyde with bovine serum albumin and casein. Histochemie 17, 151. 

Moore, J.F., and Ward, W.H. (1956) Cross-linking of bovine plasma albumin with wool keratin. /. Am. Chem. Soc. 78, 2414. 

A complete physical examination and laboratory analysis are needed to rule out secondary causes and to assess kyphosis and back pain. Laboratory testing may include complete blood count, liver function tests, creatinine, urea nitrogen, calcium, phosphorus, alkaline phosphatase, albumin, thyroid-stimulating hormone, free testosterone, 25-hydroxyvitamin D, and 24-hour urine concentrations of calcium and phosphorus. Urine or serum biomarkers (e.g., cross-linked N-telopeptides of type 1 collagen, osteocalcin) are sometimes used. 

We have observed that such proteins as CaM and bovine serum albumin (BSA) can be developed at the air-water interface to form monolayer protein films. In previous works, the developed BSA monolayer was stabilized by cross-linking with a bifunctional reagent immediately after the preparation of protein monolayer. The BSA thin film thus prepared can be employed as a passive material, e.g., an ultrathin protein film for a matrix of enzyme-linked immunosorvent assays. 

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