Poly-D-lysine

Malcolm (1973, 1975) reported possible observable differences between the pressure-area curves of poly(L-alanine) mixed with poly(D-a-amino-n-butyric acid) and the corresponding mixture containing poly(D-alanine). Shafer (1974) observed differences in the film pressure between (/ )-phosphatidyl serine with poly-L-lysine and the corresponding film with poly-D-lysine injected under the film. 

The relevance of such a diastereomer discrimination to the transport of chiral molecules, such as pharmaceuticals or biochemicals, through hydrophobic barriers, such as cell membranes, is obvious. Furthermore, since poly(DL-lysine) followed the same general pattern of behavior displayed by the other three samples, the observed surface-pressure changes probably were not due to helicalization of the polypeptide. Whereas poly(L-lysine) and poly(D-lysine) form helices with opposite screw sense, the random copolymer poly(DL-lysine) is to a large extent prevented from forming helices. 

The hyperbranched poly( acrylic acid) graft films -C02H-rich interface on polyethylene can be modified by noncovalent methods just like CO2H-rich interfaces of PAA/Au grafts. This was shown by treating deprotonated 3-PAA/PE films with cationic polyelectrolytes like poly-D-lysine, and amine terminated PAMAM dendrimers at pH 7 [31]. Equation 10 illustrates the entrapment of PAMAM dendrimers in a 3-poly(sodium acrylate)/PE film. In these cases, polyvalent entrapment of the cationic electrolyte was evidenced in the ATR-IR spectriun by the appearance of amide C = O and N - H peaks of the guest dendrimer that were not present in the host 3-poly(sodium acrylate)/PE film. 

Fig. 18. The in vivo fluorescence time dependence after a bolus injection of fluorescein labeled poly-D-lysine in a single rat pre-kidney ligation (Normal) and post kidney ligation (Ligated). The solid line is a single exponential fit to the measured data...

Shen, W. C., Ryser, H. J., and LaManna, L. Disulfide spacer between methotrexate and poly(D-lysine). A probe for exploring the reductive process in endocytosis. J. Biol. Chem. 260 10905-10908, 1985. 

Fig. 16 Light microscopic images of tissue capsule surrounding titanium implants with a DNA and poly-D-lysine complex coating. After 12 weeks of implantation, all implants were surrounded by a relatively mature fibrous capsule without the presence of inflammatory cells at the implant interface. Reprinted with permission from [126]...

Attachment of suspension cells to coverslips facilitates labeling and washing. Fixed cells are placed on poly-D-lysine coated coverslips in 16-mm well plates for 30 min at room temperature. Unattached cells are removed by aspiration and the attached cells washed with PBS. 

Fig. 4-9 ORD spectra of poly-D-lysine showing the spectra of ar-helical and disordered conformations. (Units of (oj are degrees mLdm-1g. )...

Cell Attachment to MAP. The attachment of two cell types, one anchorage-dependent and the other anchorage-independent, was compared over time on Cell-Tak adhesive-coated dishes with the attachment on other commercially available factors. BHK-21 cells normally attach and grow in monolayers. Figure 1A graphically shows the attachment of BHK-21 cells, which attained 70 to 90% efficiency in 20 min to laminin, fibronectin, and Cell-Tak adhesive and 60% to poly-D-lysine. Maximum attachment occurred at a faster rate on Cell-Tak protein, where 90% efficiency was achieved in 12.5 min. The anchorage-independent, or suspension cell line, U-937, achieved 75-85% attachment efficiency on Cell-Tak adhesive (Figure IB) but less than 30% attachment to any of the other factors. 

Figure 1. The attachment of adherent BHK-21 cells (Figure 1A) and nonadherent U-937 cells (Figure IB) to Cell-Tak adhesive, collagen, O poly-D-lysine, + laminin, X fibronectin, A and plastic, y, was monitored by counting unattached cells at 5, 12.5, and 20 min. Data were then converted mathematically to percent attached of those seeded.

Figure 5.32 Poly (D-lysine) and (L-lysine) form helices in water above pH = 10. Mixture of the M- and P-helices leads to rapid precipitation of a -sheet structure.

Attachment factors - fibronectin, poly-D-lysine, collagen, serum-spreading factor, etc. 

Originally polymers of L-lysine were used but because this is the metabolically active form of the amino acid, some workers prefer to use poly-D-lysine. A simple procedure for coating surfaces follows. 

Poly-D-lysine, lyophihzed and gamma-irradiated (Sigma)... 

Instruments/ equipment ICR-8000 flame atomic absorption spectrometer (Aurora Biomed Inc., Vancouver, BC, Canada), Poly-D-lysine-coated 96-well assay plates (Becton Dickinson, Billerica, MA). 

Poly-D-lysine (Sigma-Aldrich BV, Cat. P-7280) coating solution is prepared in a 1 mg/ml stock solution in sterile MilU-Q water and stored in 1 ml aliquots at -20°C in 100-ml bottles. Poly-D-lysine working solution of lOpg/ml is prepared by dilution in PBS, kept at 4°C, and can be used for no longer than 6 weeks. 

Culture flasks for seeding rat astrocytes are coated by adding 6 ml Poly-d-Lysine (10 xg/ml) per 250-ml culture flask (T75) and left overnight on a shaker at room temperature. Flasks are aspirated and dried for 3 h (not longer). After drying, the flasks are rinsed 3 times with PBS before seeding the cells. 

Spin the cell suspension for 5min at l.OOOrpm (180g) and resuspend the pellet in 9 ml DMEM + S and plate the cells in nine Poly-d-Lysine coated flasks containing 10ml DMEM + S 1 ml to each. 

Shen WC, Ryser HJP. Poly(L-lysine) and poly(D-lysine) conjugates of methotrexate— different inhibitory effect of drag resistant cells. Mol Pharmacol 1979 16 614-622. 

MTX(poly-L- and poly-D-lysine) were synthesized according to a procedure first outlined by Ryser and Shen (14). 0.1 ml of a... 

---