Income taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule loss before income taxes

	Years Ended December 31,
	2021			2020
United States loss before income taxes	$	(8,504,426	)	$	(12,041,331	)
China loss before income taxes		(586,073	)		(638,107	)
Total loss before income taxes	$	(9,090,499	)	$	(12,679,438	)

Schedule of income taxes expense (benefit)

	Years Ended December 31,
	2021			2020
Current:
U.S. federal	$	-		$	-
U.S. state and local		-			-
China		-			-
Total current income taxes expense	$	-		$	-
Deferred:
U.S. federal	$	(1,810,264	)	$	(2,333,680	)
U.S. state and local		(612,904	)		(790,117	)
China		(152,015	)		(132,578	)
Total deferred income taxes (benefit)	$	(2,575,183	)	$	(3,256,375	)
Change in valuation allowance		2,575,183			3,256,375
Total income taxes expense	$	-		$	-

Schedule of differences between U.S. statutory rate and Company's effective tax rate

	Years Ended December 31,
	2021			2020
U.S. federal rate		21.0	%		21.0	%
U.S. state rate		6.7	%		6.8	%
Non-US rate differential		0.3	%		0.2	%
Prior year true-up		4.9	%		0.0	%
U.S. valuation allowance		(32.9	)%		(28.0	)%
Total provision for income taxes		0.0	%		0.0	%

Schedule of deferred income tax assets

	December 31, 2021			December 31, 2020
Deferred tax assets
Stock-based compensation	$	3,696,463		$	3,667,375
Disallowed business interest deduction		103,567			33,384
Accrued directors’ compensation		80,816			-
Lease liability		23,156			40,291
Net operating loss carryforward		11,441,503			9,079,127
Total deferred tax assets, gross		15,345,505			12,820,177
Valuation allowance		(15,224,188	)		(12,649,005	)
Total deferred tax assets, net	$	121,317		$	171,172
Deferred tax liabilities
Fixed assets and intangible assets book/tax basis difference		(101,534	)		(132,568	)
Right-of-use assets		(19,783	)		(38,604	)
Total deferred tax liabilities	$	(121,317	)	$	(171,172	)
Net deferred tax assets	$	-		$	-