DESCRIPTION

SPARC, also known as ON (Osteonectin) or BM-40 (Basement-membrane protein 40), is an extracellular glycoprotein. SPARC belongs to a group of matricellular proteins defined as secreted components that do not contribute directly to the formation of structural elements but serve to modulate cell-matrix interactions and cellular functions. SPARC is expressed at high levels in bone tissue, is distributed widely in many other tissues and cell types, and is associated generally with tissues undergoing morphogenesis, remodeling and wound repair. It elicits changes in cell shape, inhibits cell-cycle progression, and influences the synthesis of extracellular matrix. Altered expression of SPARC has been reported in a variety of cancers, which include breast, ovarian, colorectal, and pancreatic cancer as well as melanoma and glioblastomas.

PRINCIPLE OF THE ASSAY

Sandwich ELISA structure (Detection antibody labeled with HRP) A capture antibody is pre-coated onto the bottom of wells which binds to analyte of interest. A detection antibody labeled with HRP also binds to the analyte. TMB acts as the HRP substrate and the solution color will change from colorless to blue. A stop solution containing sulfuric acid turns solution yellow. The color intensity is proportional to the quantity of bound protein which is measurable at 450 nm with the correction wavelength set at 630 nm.

PRECISION

Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested 8 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 16 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (ng/mL)	SD	CV%
1	8	1,462.81	59.40	4.06
2	8	354.62	11.06	3.12
3	8	83.84	3.86	4.60

Inter-assay Precision

Sample	n	Mean (ng/mL)	SD	CV%
1	16	1,542.67	130.69	8.47
2	16	368.44	22.78	6.18
3	16	85.75	5.98	6.97

RECOVERY

The recovery of human SPARC spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human serum	1:800	91	87-97
	1:1,600	92	88-95
Cell culture supernatant	1:640	92	90-95
Human milk	1:16	76	75-79

LINEARITY

To assess the linearity of the assay, samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. (The human serum was initially diluted 1:100. The cell culture supernatant was initially diluted 1:40.)

		Human serum	Cell culture supernatant	Human milk
1:2	Average% of Expected	100	100	100
	Range (%)	-	-	-
1:4	Average% of Expected	106	101	99
	Range (%)	96-116	99-103	98-99
1:8	Average% of Expected	102	90	104
	Range (%)	93-111	86-93	93-115
1:16	Average% of Expected	118	99	97
	Range (%)	112-125	94-104	92-101

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant Human SPARC produced at Sunlong Medical™.

Ordering & shipping

• Minimum order: 1 kit
• Lead time: varies with order quantity and specifications. Please consult your local distributor or our sales team for confirmation
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• Price: USD, per kit (48T / 96T options available)