Comparative optical study of biofluids (serum, urine, hemodialysate) and carbon nanodots (CND) aqueous solutions has been done. Biofluids were collected from chronic kidney diseases patients (CKD Pts) as well as from normal controls (NCs). Sugar derived CND and oxidized graphene solutions were prepared and used. Fluorescence and excitation spectra have mainly been measured and compared for two sets of subjects. For both family of subjects typical fluorescence with parameters λ exсmax / λ emmax = 320±5/420±5 nm is observed and has many analogeous properties. New effective method of additional similarity identification with use of aluminum salts Al 2 (SO 4 ) 3 , Al (N0 3 ) 3 and AlCl 3 is proposed. Aluminum ions induce the fluorescence band at 380 nm in all substances investigated. Plenty of similar features (12) in optical properties create a united platform for further investigation of the topic -the nature of endogenous near UV and visible fluorescence in biofluids and CND.

Comparative optical study of bio°uids (serum, urine, hemodialysate) by concentration change of endogenous visible°uorescence substance (VFS) has been carried out. Bio°uids were collected from chronic kidney diseases (CKD) patients (Pts) as well as from healthy controls (HCs). Excitation/emission spectra are similar for all samples of bio°uids di®ering only in intensity, which is higher for CKD Pts. Strong similarity enables the study of given bio°uids from a united physical platform, proposed earlier, i.e., as nanoparticles approach. Speci¯c spectral redistribution of visible°uorescence (VF) intensity as a result of dilution is revealed. The concentration change of VFS by dilution of samples manifests in nonlinear dependences in the scales \VF intensity-concentration" for serum and urine and in perfect linearity for hemodialysate (HD). The latter fact can be used in monitoring of hemodialysis procedure.

Abstract. The detection of small quantities of proteinuria has gained significance as multiple studies have demonstrated its diagnostic, pathogenic, and prognostic importance. More than 260 samples of urine taken from the patients suffering chronic kidney disease (CKD), diabetes and hypertension have been analysed in the certified laboratory, with urine analyser H-50 (urine test strips) and with an optoelectronic setup specially designed for this study. Albumin, protein and creatinine concentrations have been determined in the laboratory and the data thoroughly analysed with the aim to find new approaches to tackle the lowered level proteinuria problems. Special attention has been paid to a particular screening focus group of 16 patients all having normal or slightly abnormal levels of albumin in parallel with enhanced levels of total protein (45% cases) up to 0.4 g/L. A fair correlation between the maxima in the protein, protein/creatinine, protein/albumin values and CKD in the focus group has been observed. The urine test strips method gave 94% negative false results for the focus group whereas the new sensor has shown in all cases the presence of proteins. The sensor signals higher than the mean in this focus group were obtained for the donors with the diagnosed CKD and some other diseases. The new method is based on the optical absorption measurements (285 nm) in the protein fractions received with use of the commercial desalting columns PD-10. The method can be applied in the wide region of protein concentrations from ≤0.1 g/L up to the levels of severe proteinuria (~10g/L).

Point-of-care testing (POCT) devices are becoming increasingly popular in the medical community as an alternative to conventional laboratory testing, especially for home treatments or other forms of outpatient care. Multiple-use chemical sensors with minimal requirements for disposables are among the most practical and cost-effective POC diagnostic instruments, especially in managing chronic conditions. An affordable, simple, and easy-to-use optical sensor based on fast protein liquid chromatography with direct UV absorption detection was developed for the rapid determination of the total protein concentration in effluent peritoneal dialysate and for the assessment of protein losses in end-stage renal disease (ESRD) patients on constant ambulatory peritoneal dialysis (CAPD). The sensor employs non-disposable PD-10 desalting columns for the separation of molecules with different molecular weights and a deep UV LED (maximum at 285 nm) as a light source for optical detection. The analytic procedure is relatively simple, takes 10–15 min, and potentially can be performed by patients themselves or nursing staff without laboratory training. Preliminary clinical trials on a group of 23 patients on CAPD revealed a good concordance between the protein concentrations in dialysate samples measured with the sensor and an automated biochemical analyzer; the mean relative error was about 10%, which is comparable with routine clinical laboratory methods.

We report the development of a new mouse anti-titin monoclonal antibody, named MAb Tit1 5H1.1, using the synthetic peptide corresponding to an amino acid sequence in the A-band of the titin molecule as immunogen. In the human skeletal muscle, MAb Tit1 5H1.1 reveals a clearly striated staining pattern, reacting with the A-band of the sarcomere. Electrophoretic, immunoblotting, and amino acid sequence analyses with ESI-MS/MS of human skeletal muscle tissue proved the target antigen of MAb Tit1 5H1.1 to be titin. The antibody reacts with titin also in non-muscle cells, producing a punctate pattern in cytoplasm and the nucleus. The most striking finding was a clear reaction of MAb Tit1 5H1.1 with centrioles in all cell types investigated so far. Immunocytochemical co-localization study with ninein-specific antibodies confirmed that the target antigen of MAb Tit1 5H1.1 is a centriole-associated protein. Experiments of the inhibition of synthesis of titin using titin siRNA duplex for the destruction of titin mRNA have shown a decreased staining of centrioles by MAb Tit1 5H1.1 in non-muscle cells and support the proposal that the target antigen of MAb is indeed titin. We suggest this anti-titin monoclonal antibody could be a valuable tool in the study of titin function and its subcellular location, both in muscle and non-muscle cells.