MaxCyte, Inc.

("MaxCyte" or the "Company")

Exercise of options and PDMR dealing

ROCKVILLE, MD,November 6, 2024:MaxCyte Inc., (NASDAQ: MXCT; LSE: MXCT), a leading, cell-engineering focused company providing enabling platform technologies to advance the discovery, development, and commercialization of next-generation cell therapeutics and to support innovative, cell-based research, announces that on5 November 2024, as per a filing lodged with theU.S. Securities and Exchange Commission,Stanley Erck, a Non-Executive Director of the Company, exercised options over 47,689 shares of common stock of$0.01of the Company ("Common Stock") ("Exercise") in aggregate. The 47,689 new shares of Common Stock were issued pursuant to the Company's existing its block admission facility and were sold byStanley Erckat a price range between$3.610and$3.755per Common Stock ("Sale"). The sold shares represent approximately 8.04% ofStanley Erck'stotal equity and option holdings in the Company's stock capital, respectively.

Following the Exercise and Sale,Stanley Erckholds 247,751 shares of Common Stock representing 0.2% of the issued stock capital of the Company. Following the Exercise,Stanley Erckholds a further 276,501 options over Common Stock and 21,367 restricted stock units.

The sales and option exercises were effected pursuant to a Rule 10b5-1 trading plan adopted byStanley Erckon12 March 2024relating solely to the sale of shares acquired from exercise of options that expire on11 November 2024.

MaxCyte Contacts:

US IR Adviser

Gilmartin Group

David Deuchler, CFA

+1 415-937-5400

ir@maxcyte.com

Nominated Adviser and Joint Corporate Broker

Panmure Liberum

Emma Earl/Freddy Crossley

Corporate Broking

Rupert Dearden

+44 (0)20 7886 2500

UKIR Adviser

ICR Healthcare

Mary-Jane Elliott

Chris Welsh

+44 (0)203 709 5700

maxcyte@icrhealthcare.com

AboutMaxCyte

AtMaxCyte, we pursue cell engineering excellence to maximize the potential of cells to improve patients' lives. We have spent more than 20 years honing our expertise by building best-in-class platforms, perfecting the art of the transfection workflow, and venturing beyond today's processes to innovate tomorrow's solutions. Our ExPERTTM platform, which is based on our Flow Electroporation® technology, has been designed to support the rapidly expanding cell therapy market and can be utilized across the continuum of the high-growth cell therapy sector, from discovery and development through commercialization of next-generation, cell-based medicines. The ExPERT family of products includes: four instruments, the ATxTM, STxTM, GTxTM and VLx TM; a portfolio of proprietary related processing assemblies or disposables; and software protocols, all supported by a robust worldwide intellectual property portfolio. By providing our partners with the right technology platform, as well as scientific, technical and regulatory support, we aim to guide them on their journey to transform human health. Learn more atmaxcyte.comand follow us on X (formerly Twitter) and LinkedIn.

NOTIFICATION AND PUBLIC DISCLOSURE OF TRANSACTIONS BY PERSONS DISCHARGING MANAGERIAL RESPONSIBILITIES AND PERSONS CLOSELY ASSOCIATED WITH THEM